Classical Authors Writing About the Ancient Celts

Julius Caesar, De Bello Gallico, Book VI, Ch.13-20:

[Caesar (C. Iulius, 102–44 BC), statesman and soldier, defied the dictator Sulla; served in the Mithridatic wars and in Spain; pushed his way in Roman politics as a “democrat” against the senatorial government; was the real leader of the coalition with Pompey and Crassus; conquered all Gaul for Rome; attacked Britain twice; was forced into civil war; became master of the Roman world; and achieved wide-reaching reforms until his murder. We have his books of Commentarii (notes): eight on his wars in Gaul, 58–52 BC, including the two expeditions to Britain 55–54 BC, and three on the civil war of 49–48 BC.]

13. Throughout all Gaul there are two orders of those men who are of any rank and dignity: for the commonality is held almost in the condition of slaves, and dares to undertake nothing of itself, and is admitted to no deliberation. The greater part, when they are pressed either by debt, or the large amount of their tributes, or the oppression of the more powerful, give themselves up in vassalage to the nobles, who possess over them the same rights without exception as masters over their slaves. But of these two orders, one is that of the Druids, the other that of the knights. The former are engaged in things sacred, conduct the public and the private sacrifices, and interpret all matters of religion. To these a large number of the young men resort for the purpose of instruction, and they [the Druids] are in great honor among them. For they determine respecting almost all controversies, public and private; and if any crime has been perpetrated, if murder has been committed, if there be any dispute about an inheritance, if any about boundaries, these same persons decide it; they decree rewards and punishments; if any one, either in a private or public capacity, has not submitted to their decision, they interdict him from the sacrifices. This among them is the most heavy punishment. Those who have been thus interdicted are esteemed in the number of the impious and the criminal: all shun them, and avoid their society and conversation, lest they receive some evil from their contact; nor is justice administered to them when seeking it, nor is any dignity bestowed on them. Over all these Druids one presides, who possesses supreme authority among them. Upon his death, if any individual among the rest is pre-eminent in dignity, he succeeds; but, if there are many equal, the election is made by the suffrages of the Druids; sometimes they even contend for the presidency with arms. These assemble at a fixed period of the year in a consecrated place in the territories of the Carnutes, which is reckoned the central region of the whole of Gaul. Hither all, who have disputes, assemble from every part, and submit to their decrees and determinations. This institution is supposed to have been devised in Britain, and to have been brought over from it into Gaul; and now those who desire to gain a more accurate knowledge of that system generally proceed thither for the purpose of studying it.

14. The Druids do not go to war, nor pay tribute together with the rest; they have an exemption from military service and a dispensation in all matters. Induced by such great advantages, many embrace this profession of their own accord, and [many] are sent to it by their parents and relations. They are said there to learn by heart a great number of verses; accordingly some remain in the course of training twenty years. Nor do they regard it lawful to commit these to writing, though in almost all other matters, in their public and private transactions, they use Greek characters. That practice they seem to me to have adopted for two reasons; because they neither desire their doctrines to be divulged among the mass of the people, nor those who learn, to devote themselves the less to the efforts of memory, relying on writing; since it generally occurs to most men, that, in their dependence on writing, they relax their diligence in learning thoroughly, and their employment of the memory. They wish to inculcate this as one of their leading tenets, that souls do not become extinct, but pass after death from one body to another, and they think that men by this tenet are in a great degree excited to valor, the fear of death being disregarded. They likewise discuss and impart to the youth many things respecting the stars and their motion, respecting the extent of the world and of our earth, respecting the nature of things, respecting the power and the majesty of the immortal gods.

15. The other order is that of the knights. These, when there is occasion and any war occurs (which before Caesar's arrival was for the most part wont to happen every year, as either they on their part were inflecting injuries or repelling those which others inflected on them), are all engaged in war. And those of them most distinguished by birth and resources, have the greatest number of vassals and dependents about them. They acknowledge this sort of influence and power only.

16. The nation of all the Gauls is extremely devoted to superstitious rites; and on that account they who are troubled with unusually severe diseases, and they who are engaged in battles and dangers, either sacrifice men as victims, or vow that they will sacrifice them, and employ the Druids as the performers of those sacrifices; because they think that unless the life of a man be offered for the life of a man, the mind of the immortal gods can not be rendered propitious, and they have sacrifices of that kind ordained for national purposes. Others have figures of vast size, the limbs of which formed of osiers they fill with living men, which being set on fire, the men perish enveloped in the flames. They consider that the oblation of such as have been taken in theft, or in robbery, or any other offense, is more acceptable to the immortal gods; but when a supply of that class is wanting, they have recourse to the oblation of even the innocent.

17. They worship as their divinity, Mercury in particular, and have many images of him, and regard him as the inventor of all arts, they consider him the guide of their journeys and marches, and believe him to have great influence over the acquisition of gain and mercantile transactions. Next to him they worship Apollo, and Mars, and Jupiter, and Minerva; respecting these deities they have for the most part the same belief as other nations: that Apollo averts diseases, that Minerva imparts the invention of manufactures, that Jupiter possesses the sovereignty of the heavenly powers; that Mars presides over wars. To him, when they have determined to engage in battle, they commonly vow those things which they shall take in war. When they have conquered, they sacrifice whatever captured animals may have survived the conflict, and collect the other things into one place. In many states you may see piles of these things heaped up in their consecrated spots; nor does it often happen that any one, disregarding the sanctity of the case, dares either to secrete in his house things captured, or take away those deposited; and the most severe punishment, with torture, has been established for such a deed.

18. All the Gauls assert that they are descended from the god Dis, and say that this tradition has been handed down by the Druids. For that reason they compute the divisions of every season, not by the number of days, but of nights; they keep birthdays and the beginnings of months and years in such an order that the day follows the night. Among the other usages of their life, they differ in this from almost all other nations, that they do not permit their children to approach them openly until they are grown up so as to be able to bear the service of war; and they regard it as indecorous for a son of boyish age to stand in public in the presence of his father.

19. Whatever sums of money the husbands have received in the name of dowry from their wives, making an estimate of it, they add the same amount out of their own estates. An account is kept of all this money conjointly, and the profits are laid by: whichever of them shall have survived [the other], to that one the portion of both reverts together with the profits of the previous time. Husbands have power of life and death over their wives as well as over their children: and when the father of a family, born in a more than commonly distinguished rank, has died, his relations assemble, and, if the circumstances of his death are suspicious, hold an investigation upon the wives in the manner adopted toward slaves; and, if proof be obtained, put them to severe torture, and kill them. Their funerals, considering the state of civilization among the Gauls, are magnificent and costly; and they cast into the fire all things, including living creatures, which they suppose to have been dear to them when alive; and, a little before this period, slaves and dependents, who were ascertained to have been beloved by them, were, after the regular funeral rites were completed, burnt together with them.

20. Those states which are considered to conduct their commonwealth more judiciously, have it ordained by their laws, that, if any person shall have heard by rumor and report from his neighbors any thing concerning the commonwealth, he shall convey it to the magistrate, and not impart it to any other; because it has been discovered that inconsiderate and inexperienced men were often alarmed by false reports, and driven to some rash act, or else took hasty measures in affairs of the highest importance. The magistrates conceal those things which require to be kept unknown; and they disclose to the people whatever they determine to be expedient. It is not lawful to speak of the commonwealth, except in council.

Diodorus Siculus, Book V, §26-32:

[Diodorus Siculus (lit. Diodorus of Sicily), Greek historian of Agyrium in Sicily, ca. 80–20 BC, wrote forty books of world history, called Library of History, in three parts: mythical history of peoples, non-Greek and Greek, to the Trojan War; history to Alexander’s death (323 BC); history to 54 BC. Of this we have complete Books I–V (Egyptians, Assyrians, Ethiopians, Greeks) and Books XI–XX (Greek history 480–302 BC); and fragments of the rest. He was an uncritical compiler, but used good sources and reproduced them faithfully. He is valuable for details unrecorded elsewhere, and as evidence for works now lost.]

27. … around their wrists and arms they wear bracelets, around their necks heavy rings of solid gold, and huge rings they wear as well, and even corselets of gold. And a peculiar and striking practice is found among the upper Celts, in connection with the sacred precincts of the gods; for in the temples and precincts made consecrate in their land, a great amount of gold has been deposited as a dedication to the gods, and not a native of the country ever touches it because of religious scruple, although the Celts are an exceedingly covetous people.

28. The Gauls are tall of body, with rippling muscles, and white of skin, and their hair is blond, and not only naturally so, but they also make it their practice by artificial means to increase the distinguishing colour which nature has given it. For they are always washing their hair in lime-water, and they pull it back from their forehead to the top of the head and back to the nape of the neck, with the result that their appearance is like that of Satyrs and Pans, since the treatment of their hair makes it so heavy and coarse that it differs in no respect from the manes of horses. Some of them shave the beard, but others let it grow a little; and the nobles shave their cheeks, but they let the moustache grow until it covers the mouth. Consequently, when they are eating, their moustaches become entangled in the food, and when they are drinking, the beverage passes, as it were, through a kind of strainer. When they dine, they all sit, not upon chairs, but upon the ground, using for cushions the skins of wolves or of dogs. The service at the meals is performed by the youngest children, both male and female, who are of suitable age; and near at hand are their fireplaces heaped with coals, and on them are cauldrons and spits holding whole pieces of meat. Brave warriors they reward with the choicest portions of the meat, in the same manner as the poet introduces Ajax as honoured by the chiefs after he returned victorious from his single combat with Hector:

“To Ajax then were given of the chine
  Slices, full-length, unto his honour.”

They invite strangers to their feasts, and do not inquire until after the meal who they are and of what things they stand in need. And it is their custom, even during the course of the meal, to seize upon any trivial matter as an occasion for keen disputation and then to challenge one another to single combat, without any regard for their lives; for the belief of Pythagoras prevails among them, that the souls of men are immortal and that after a prescribed number of years they commence upon a new life, the soul entering another body. Consequently, we are told, at the funerals of their dead some cast letters upon the pyre which they have written to their deceased kinsmen, as if the dead would be able to read these letters.

29. In their journeyings and when they go into battle the Gauls use chariots drawn by two horses, which carry the charioteer and the warrior; and when they encounter cavalry in the fighting they first hurl javelins at the enemy and then step down from their chariots and join battle with their swords. Certain of them despise death to such a degree that they enter the perils of battle without protective armour and with no more than a girdle about their loins. They bring along to war also their free men to serve them, choosing them out from among the poor, and these attendants they use in battle as charioteers and as shield-bearers. It is also their custom, when they are formed for battle, to step out in front of the line and to challenge the most valiant men from among their opponents to single combat, brandishing their weapons in front of them to terrify their adversaries. And when any man accepts the challenge to battle, they then break forth into a song in praise of the valiant deeds of their ancestors and in boast of their own high achievements, reviling all the while and belittling their opponent, and trying, in a word, by such talk to strip him of his bold spirit before the combat. When their enemies fall they cut off their heads and fasten them about the necks of their horses; and turning over to their attendants the arms of their opponents, all covered with blood, they carry them off as booty, singing a paean over them and striking up a song of victory, and these first fruits of battle they fasten by nails upon their houses, just as men do, in certain kinds of hunting, with the heads of wild beasts they have mastered. The heads of their most distinguished enemies they embalm in cedar-oil and carefully preserve in a chest, and these they exhibit to strangers, gravely maintaining that in exchange for this head some one of their ancestors, or their father, or the man himself, refused the offer of a great sum of money. And some men among them, we are told, boast that they have not accepted an equal weight of gold for the head they show, displaying a barbarous sort of greatness of soul; for not to sell that which constitutes a witness and proof of one's valour is a noble thing, but to continue to fight against one of our own race, after he is dead, is to descend to the level of beasts.

30. The clothing they wear is striking – shirts which have been dyed and embroidered in varied colours, and breeches, which they call in their language bracae; and they wear striped coats, fastened by a buckle on the shoulder, heavy for winter wear and light for summer, in which are set checks, close together and of various hues. For armour they use long shields, as high as a man, which are wrought in a manner peculiar to them, some of them even having the figures of animals embossed on them in bronze, and these are skilfully worked with an eye not only to beauty but also protection. On their heads they put bronze helmets which have large embossed figures standing out from them and give an appearance of great size to those who wear them; for in some cases horns are attached to the helmet so as to form a single piece, in other cases images of the fore-parts of birds or four-footed animals. Their trumpets are of peculiar nature and such as barbarians use, for when they are blown upon they give forth a harsh sound, appropriate to the tumult of war. Some of them have iron cuirasses, chain-wrought, but others are satisfied with the armour which Nature has given them and go into battle naked. In place of the short sword they carry long broadswords which are hung on chains of iron or bronze and are worn along the right flank. And some of them gather up their shirts with belts plated with gold or silver. The spears they brandish, which they call lanciae, have iron heads a cubit in length and even more, and a little under two palms in breadth; for their swords are not shorter than the javelins of other peoples, and the heads of their javelins are larger than the swords of others. Some of these javelins come from the forge straight, others twist in and out in spiral shapes for their entire length, the purpose being that the thrust may not only cut the flesh, but mangle it as well, and that the withdrawal of the spear may lacerate the wound.

31. The Gauls are terrifying in aspect and their voices are deep and altogether harsh; when they meet together they converse with few words and in riddles, hinting darkly at things for the most part and using one word when they mean another; and they like to talk in superlatives, to the end that they may extol themselves and deprecate all other men. They are also boasters and threateners and are fond of pompous language, and yet they have sharp wits and are not without cleverness at learning. … Philosophers, as we may call them, and men learned in religious affairs are unusually honoured among them and are called by them Druids. The Gauls likewise make use of diviners, accounting them worthy of high approbation, and these men foretell the future by means of the flight or cries of birds and of the slaughter of sacred animals, and they have all the multitude subservient to them. They also observe a custom which is especially astonishing and incredible, in case they are taking thought with respect to matters of great concern; for in such cases they devote to death a human being and plunge a dagger into him in the region above the diaphragm, and when the stricken victim has fallen they read the future from the manner of his fall and from the twitching of his limbs, as well as from the gushing of blood, having learned the practice of observing such matters. And it is a custom of theirs that no one should perform a sacrifice without a “philosopher”; for thank-­offerings should be rendered to the gods, they say, by the hands of men who are experienced in the nature of the divine, and who speak, as it were, the language of the gods, and it is also through the mediation of such men, they think, that blessings likewise should be sought. Nor is it only in the exigencies of peace, but in their wars as well, that they obey, before all others, these men and their chanting poets, and such obedience is observed not only by their friends but also by their enemies; many times, for instance, when two armies approach each other in battle with swords drawn and spears thrust forward, these men step forth between them and cause them to cease, as though having cast a spell over certain kinds of wild beasts. In this way, even among the wildest barbarians, does passion give place before wisdom, and Ares stands in awe of the Muses.

32. … The women of Gaul are not only like their great stature but they are a match for them in courage as well. … The most savage peoples among them are those who dwell beneath the Bears and on the borders of Scythia, and some of these, we are told, eat human beings, even as the Britons do who dwell on Iris [i.e. Ireland], as it is called. And since the valour of these peoples and their savage ways have been famed abroad, some men say that it was they who in ancient times overran all Asia and were called Cimmerians, time having slightly corrupted the word into the name of Cimbrians, as they are now called. For it has been their ambition from old to plunder, invading for this purpose the lands of others, and to regard all men with contempt. For they are the people who captured Rome, who plundered the sanctuary at Delphi, who levied tribute upon a large part of Europe and no small part of Asia, and settled themselves upon the lands of the peoples they had subdued in war, being called in time Greco-­Gauls, because they became mixed with the Greeks, and who, as their last accomplishment, have destroyed many large Roman armies. And in pursuance of their savage ways they manifest an outlandish impiety also with respect to sacrifices; for their criminals they keep prisoner for five years and then impale in honour of the gods, dedicating them together with many other offerings of first-fruits and constructing pyres of great size. Captives are also used by them as victims for their sacrifices in honour of the gods. Certain of them likewise slay, together with human beings, such animals as are taken in war, or burn them or do away with them in some other vengeful fashion. …

Strabo, Geography, Book IV, Ch.4:

[Strabo (64/63 BC–ca. 24 AD), Greek historian, geographer, and philosopher.  Strabo’s work, usually referred to by modern scholars as the Geography, is a description of the cultural and geo-political world of Strabo’s day, as well as an account of how the physical world was perceived at that time.]

4.4.4. Among all the Gallic peoples, generally speaking, there are three sets of men who are held in exceptional honour; the Bards, the Vates and the Druids. The Bards are singers and poets; the Vates, diviners and natural philosophers; while the Druids, in addition to natural philosophy, study also moral philosophy. The Druids are considered the most just of men, and on this account they are entrusted with the decision, not only of the private disputes, but of the public disputes as well; so that, in former times, they even arbitrated cases of war and made the opponents stop when they were about to line up for battle, and the murder cases, in particular, had been turned over to them for decision. Further, when there is a big yield from these cases, there is forthcoming a big yield from the land too, as they think. However, not only the Druids, but others as well, say that men's souls, and also the universe, are indestructible, although both fire and water will at some time or other prevail over them.

4.4.5. In addition to their trait of simplicity and high-spiritedness, that of witlessness and boastfulness is much in evidence, and also that of fondness for ornaments; for they not only wear golden ornaments — both chains round their necks and bracelets round their arms and wrists — but their dignitaries wear garments that are dyed in colours and sprinkled with gold. And by reason of this levity of character they not only look insufferable when victorious, but also scared out of their wits when worsted. Again, in addition to their witlessness, there is also that custom, barbarous and exotic, which attends most of the northern tribes — I mean the fact that when they depart from the battle they hang the heads of their enemies from the necks of their horses, and, when they have brought them home, nail the spectacle to the entrances of their homes. At any rate, Poseidonius says that he himself saw this spectacle in many places, and that, although at first he loathed it, afterwards, through his familiarity with it, he could bear it calmly. The heads of enemies of high repute, however, they used to embalm in cedar-oil and exhibit to strangers, and they would not deign to give them back even for a ransom of an equal weight of gold. But the Romans put a stop to these customs, as well as to all those connected with the sacrifices and divinations that are opposed to our usages. They used to strike a human being, whom they had devoted to death, in the back with a sabre, and then divine from his death-struggle. But they would not sacrifice without the Druids. We are told of still other kinds of human sacrifices; for example, they would shoot victims to death with arrows, or impale them in the temples, or, having devised a colossus of straw and wood, throw into the colossus cattle and wild animals of all sorts and human beings, and then make a burnt-offering of the whole thing.

4.4.6. In the ocean, he says, there is a small island, not very far out to sea, situated off the outlet of the Liger River; and the island is inhabited by women of the Samnitae, and they are possessed by Dionysus and make this god propitious by appeasing him with mystic initiations as well as other sacred performances; and no man sets foot on the island, although the women themselves, sailing from it, have intercourse with the men and then return again. And, he says, it is a custom of theirs once a year to unroof the temple and roof it again on the same day before sunset, each woman bringing her load to add to the roof; but the woman whose load falls out of her arms is rent to pieces by the rest, and they carry the pieces round the temple with the cry of "Ev-ah," and do not cease until their frenzy ceases; and it is always the case, he says, that some one jostles the woman who is to suffer this fate. But the following story which Artemidorus has told about the case of the crows is still more fabulous: there is a certain harbour on the ocean-coast, his story goes, which is surnamed "Two Crows," and in this harbour are to be seen two crows, with their right wings somewhat white; so the men who have disputes about certain things come here, put a plank on an elevated place, and then throw on barley cakes, each man separately; the birds fly up, eat some of the barley cakes, scatter the others; and the man whose barley cakes are scattered wins his dispute. Now although this story is more fabulous, his story about Demeter and Core is more credible. He says that there is an island near Britain on which sacrifices are performed like those sacrifices in Samothrace that have to do with Demeter and Core. And the following, too, is one of the things that are believed, namely, that in Celtica there grows a tree like a fig-tree, and that it brings forth a fruit similar to a Corinthian-wrought capital of a column; and that, if an incision be made, this fruit exudes a sap which, as used for the smearing of arrows, is deadly. And the following, too, is one of the things that are repeated over and over again, namely, that not only are all Celti fond of strife, but among them it is considered no disgrace for the young men to be prodigal of their youthful charms. Ephorus, in his account, makes Celtica so excessive in its size that he assigns to the regions of Celtic most of the regions, as far as Gades, of what we now call Iberia; further, he declares that the people are fond of the Greeks, and specifies many things about them that do not fit the facts of to‑day. The following, also, is a thing peculiar to them, that they endeavour not to grow fat or pot-bellied, and any young man who exceeds the standard measure of the girdle is punished. So much for Transalpine Celtica.

Athenaeus, Deipnosophistae, Book IV, §151-152, 154:

[Athenaeus (ca. 170–ca. 230 AD), a Greek of Naucratis in Egypt, lived in Rome and wrote a historical work now lost. Of the fifteen books of his surviving Deipnosophists (“Sophists at Dinner”), the first two and parts of the third, eleventh, and fifteenth exist only in summary, the rest apparently complete. In it he pretends to tell a friend about a banquet at a scholar’s house whither the learned guests brought extracts from poetry for recitation and discussion. Much of the matter however concerns the food provided and accessories. One learns about cooks, strange dishes, wines, menu cards, and countless other matters. Athenaeus was an antiquarian. The whole work, which mentions nearly eight hundred writers and two thousand five hundred writings, is a large treasury of information not only about table matters but also music, dances, games, and all sorts of literary subjects. And it abounds in quotations, mostly made direct by Athenaeus himself, from authors whose writings have not survived.]

Poseidonius ... in the Histories ... writes: “The Celts place hay on the ground when they serve their meals, which they take on wooden tables raised only slightly from the ground. Their food consists of a few loaves of bread, but of large quantities of meat prepared in water or roasted over coals or on spits. This they eat in a cleanly fashion, to be sure, but with a lion-like appetite, grasping whole joints with both hands and biting them off the bone; if, however, any piece proves hard to tear away, they slice it off with a small knife, which lies at hand in its sheath in a special box. Those who dwell beside rivers or by the inner and outer sea [i.e. the Mediterranean and the Atlantic] also eat fish baked with salt, vinegar and cumin. The last they also drop into their wine. They use no olive oil, on account of its rarity, and being unfamiliar, it seems to them unpleasant. When several dine together, they sit in a circle; but the mightiest among them, distinguished above the others for skill in war, or family connexions, or wealth, sits in the middle like a chorus-leader. Beside him is the host, and next on either side the others according to their respective ranks. Men­-at-arms, carrying oblong shields, stand close behind them, while their body-guards, seated in a circle directly opposite, share in the feast like their masters. The attendants serve the drink in vessels resembling our spouted cups, either of clay or silver. Similar also are the platters which they have for serving food; but others use bronze platters, others still, baskets of wood or plaited wicker. The liquor drunk in the houses of the rich is wine brought from Italy and the country round Marseilles, and is unmixed; though sometimes a little water is added. But among the needier inhabitants a beer is drunk made from wheat, with honey added; the masses drink it plain. It is called corma. They sip a little, not more than a small cupful, from the same cup, but they do it rather frequently. The slave carries the drink round from left to right and from right to left; this is the way in which they are served. They make obeisance to the gods, also, turning towards the right.”

In the twenty-third book of his Histories, Poseidonius says: “The Celts sometimes have gladiatorial contests during dinner. Having assembled under arms, they indulge in sham fights and practise feints with one another; sometimes they proceed even to the point of wounding each other, and then, exasperated by this, if the company does not intervene, they go so far as to kill. In ancient times,” he continues, “we observe that when whole joints of meat were served, the best man received the thigh. But if another claimed it, he stood up to fight it out in single combat to the death. Others, again, would collect silver or gold, or a number of jars of wine from the audience in the theatre, and having exacted a pledge that their award would be carried out, they would decree that the collection be distributed as presents to their dearest relatives; then they stretched themselves on their backs over their shields, and some one standing near would cut their throats with a sword.”

Diogenes Laertius [1^st half of 3^rd cent AD], Lives and Opinions of Eminent Philosophers, Intro:

1. Some say that the study of philosophy originated with the barbarians. In that among the Persians there existed the Magi, and among the Babylonians or Assyrians the Chaldaei, among the Indians the Gymnosophistae, and among the Celts and Gauls men who were called Druids and Semnothei, as Aristotle relates in his book on Magic, and Sotion in the twenty-third book of his Succession of Philosophers. Besides those men there were the Phoenician Ochus, the Thracian Zamolxis, and the Libyan Atlas. For the Egyptians say that Vulcan was the son of Nilus, and that he was the author of philosophy, in which those who were especially eminent were called his priests and prophets.

5. But they who say that philosophy had its rise among the barbarians, give also an account of the different systems prevailing among the various tribes. And they say that the Gymnosophists and the Druids philosophize, delivering their apophthegmns in enigmatical language, bidding men worship the gods and do no evil, and practise manly virtue.

Dion Chrysostom [ca. 40-ca. 120 AD], Orations:

49.7. Furthermore, since they cannot always be ruled by kings who are philosophers, the most powerful nations have publicly appointed philosophers as superintendents and officers for their kings. Thus the Persians, methinks, appointed those whom they call Magi, because they were acquainted with Nature and understood how the gods should be worshipped; the Egyptians appointed the priests who had the same knowledge as the Magi, devoting themselves to the service of the gods and knowing the how and the wherefore of everything; the Indians appointed Brahmins, because they excel in self-control and righteousness and in their devotion to the divine, as a result of which they know the future better than all other men know their immediate present; the Celts appointed those whom they call Druids, these also being devoted to the prophetic art and to wisdom in general. In all these cases the kings were not permitted to do or plan anything without the assistance of these wise men [the Druids], so that in truth it was they [the Druids] who ruled, while the kings became mere servants and the ministers of their will, though they sat on golden thrones, dwelt in great houses, and feasted sumptuously.

Cicero [106-43 BC], On Divination:

1.41.90. Nor is the practice of divination disregarded even among uncivilized tribes, if indeed there are Druids in Gaul — and there are, for I knew one of them myself, Divitiacus, the Aeduan, your guest and eulogist. He claimed to have that knowledge of nature which the Greeks call 'physiologia,' and he used to make predictions, sometimes by means of augury and sometimes by means of conjecture.

Ammianus Marcellinus [ca. 330-ca. 395 AD], Roman History:

15.9.4. The Druids affirm that a portion of the people was really indigenous to the soil, but that other inhabitants poured in from the islands on the coast, and from the districts across the Rhine, having been driven from their former abodes by frequent wars, and sometimes by inroads of the tempestuous sea.

15.9.8. Throughout these provinces, the people gradually becoming civilized, the study of liberal accomplishments flourished, having been first introduced by the Bards, the Eubages [Vates], and the Druids. The Bards were accustomed to employ themselves in celebrating the brave achievements of their illustrious men, in epic verso, accompanied with sweet airs on the lyre. The Eubages [Vates] investigated the system and sublime secrets of nature, and sought to explain them to their followers. Between these two came the Druids, men of loftier genius, bound in brotherhoods according to the precepts and example of Pythagoras; and their minds were elevated by investigations into secret and sublime matters, and from the contempt which they entertained for human affairs they pronounced the soul immortal.

Suetonius [ca. 69-ca. 140 AD], Life of Claudius:

25.5. He [Claudius] utterly abolished the cruel and inhuman religion of the Druids among the Gauls, which under Augustus had merely been prohibited to Roman citizens.

Pomponius Mela [writing around 43 AD], The Situation of the World:

3.2.18-19. The vestiges of savage customs still remain in the drawing of a victim’s blood while he is being led to the altar, though outright slaughter has been abolished.  Still, they have their own eloquence and wise men called Druids.  They claim to know the size of the earth and cosmos, the movements of the heavens and stars, and the will of the gods.  They teach, in caves or hidden groves, many things to the nobles in a course of instruction lasting up to twenty years.  One of their doctrines has become commonly known to the populace so that warriors might fight more bravely, that the spirit is eternal and another life awaits the spirits of the dead.  For this reason also, in past times, they would defer business and payment of debts to the next life.  There were some who would even throw themselves willingly onto the funeral pyres of their relatives so that they might live with them still.

Lucan [39-65 AD], The Civil War:

Book 1 “The Crossing of the Rubicon”

                    And those who pacify with blood accursed

                    Savage Teutates, Hesus' horrid shrines,

500              And Taranis' altars cruel as were those

                    Loved by Diana, goddess of the north;

                    All these now rest in peace.  And you, ye Bards,

                    Whose martial lays send down to distant times

                    The fame of valorous deeds in battle done,

                    Pour forth in safety more abundant song.

                    While you, ye Druids, when the war was done,

                    To mysteries strange and hateful rites returned:

                    To you alone 'tis given the gods and stars

                    To know or not to know; secluded groves

510              Your dwelling-place, and forests far remote.

                    If what ye sing be true, the shades of men

                    Seek not the dismal homes of Erebus

                    Or death's pale kingdoms; but the breath of life

                    Still rules these bodies in another age --

                    Life on this hand and that, and death between.

                    Happy the peoples 'neath the Northern Star

                    In this their false belief; for them no fear

                    Of that which frights all others: they with hands

                    And hearts undaunted rush upon the foe

520              And scorn to spare the life that shall return.

Book 3 “Massilia”

                    Now fell the forests far and wide, despoiled

450              Of all their giant trunks: for as the mound

                    On earth and brushwood stood, a timber frame

                    Held firm the soil, lest pressed beneath its towers

                    The mass might topple down.  There stood a grove

                    Which from the earliest time no hand of man

                    Had dared to violate; hidden from the sun

                    Its chill recesses; matted boughs entwined

                    Prisoned the air within.  No sylvan nymphs

                    Here found a home, nor Pan, but savage rites

                    And barbarous worship, altars horrible

460              On massive stones upreared; sacred with blood

                    Of men was every tree.  If faith be given

                    To ancient myth, no fowl has ever dared

                    To rest upon those branches, and no beast

                    Has made his lair beneath: no tempest falls,

                    Nor lightnings flash upon it from the cloud.

                    Stagnant the air, unmoving, yet the leaves

                    Filled with mysterious trembling; dripped the streams

                    From coal-black fountains; effigies of gods

                    Rude, scarcely fashioned from some fallen trunk

470              Held the mid space: and, pallid with decay,

                    Their rotting shapes struck terror.  Thus do men

                    Dread most the god unknown.  'Twas said that caves

                    Rumbled with earthquakes, that the prostrate yew

                    Rose up again; that fiery tongues of flame

                    Gleamed in the forest depths, yet were the trees

                    Unkindled; and that snakes in frequent folds

                    Were coiled around the trunks.  Men flee the spot

                    Nor dare to worship near: and e'en the priest

                    Or when bright Phoebus holds the height, or when

480              Dark night controls the heavens, in anxious dread

                    Draws near the grove and fears to find its lord.

                    Spared in the former war, still dense it rose

                    Where all the hills were bare, and Caesar now

                    Its fall commanded.  But the brawny arms

                    Which swayed the axes trembled, and the men,

                    Awed by the sacred grove's dark majesty,

                    Held back the blow they thought would be returned.

                    This Caesar saw, and swift within his grasp

                    Uprose a ponderous axe, which downward fell

490              Cleaving a mighty oak that towered to heaven,

                    While thus he spake: "Henceforth let no man dread

                    To fell this forest: all the crime is mine.

                    This be your creed."  He spake, and all obeyed,

                    For Caesar's ire weighed down the wrath of Heaven.

                    Yet ceased they not to fear.  Then first the oak,

                    Dodona's ancient boast; the knotty holm;

                    The cypress, witness of patrician grief,

                    The buoyant alder, laid their foliage low

                    Admitting day; though scarcely through the stems

500              Their fall found passage.  At the sight the Gauls

                    Grieved; but the garrison within the walls

                    Rejoiced: for thus shall men insult the gods

                    And find no punishment?  Yet fortune oft

                    Protects the guilty; on the poor alone

                    The gods can vent their ire.  Enough hewn down,

                    They seize the country wagons; and the hind,

                    His oxen gone which else had drawn the plough,

                    Mourns for his harvest.

Pliny [23/4-79 AD] Natural History:

16. 95. Upon this occasion we must not omit to mention the admiration that is lavished upon this plant by the Gauls. The Druids—for that is the name they give to their magicians—held nothing more sacred than the mistletoe and the tree that bears it, supposing always that tree to be the oak. Of itself the oak is selected by them to form whole groves, and they perform none of their religious rites without employing branches of it; so much so, that it is very probable that the priests themselves may have received their name from the Greek name [i.e. drus, which is in turn of Celtic origin] for that tree. In fact, it is the notion with them that everything that grows on it has been sent immediately from heaven, and that the mistletoe upon it is a proof that the tree has been selected by God himself as an object of his especial favour.

The mistletoe, however, is but rarely found upon the oak; and when found, is gathered with rites replete with religious awe. This is done more particularly on the fifth day of the moon, the day which is the beginning of their months and years, as also of their ages, which, with them, are but thirty years. This day they select because the moon, though not yet in the middle of her course, has already considerable power and influence; and they call her by a name which signifies, in their language, the all-healing. Having made all due preparation for the sacrifice and a banquet beneath the trees, they bring thither two white bulls, the horns of which are bound then for the first time. Clad in a white robe the priest ascends the tree, and cuts the mistletoe with a golden sickle, which is received by others in a white cloak. They then immolate the victims, offering up their prayers that God will render this gift of his propitious to those to whom he has so granted it. It is the belief with them that the mistletoe, taken in drink, will impart fecundity to all animals that are barren, and that it is an antidote for all poisons. Such are the religious feelings which we find entertained towards trifling objects among nearly all nations.

24. 62. Similar to savin is the herb known as "selago." Care is taken to gather it without the use of iron, the right hand being passed for the purpose through the left sleeve of the tunic, as though the gatherer were in the act of committing a theft. The clothing too must be white, the Feet bare and washed clean, and a sacrifice of bread and wine must be made before gathering it: it is carried also in a new napkin. The Druids of Gaul have pretended that this plant should be carried about the person as a preservative against accidents of all kinds, and that the smoke of it is extremely good for all maladies of the eyes.

The Druids, also, have given the name of "samolus" to a certain plant which grows in humid localities. This too, they say, must be gathered fasting with the left hand, as a preservative against the maladies to which swine and cattle are subject. The person, too, who gathers it must be careful not to look behind him, nor must it be laid anywhere but in the troughs from which the cattle drink.

29. 12. In addition to the above, there is another kind of egg,[1] held in high renown by the people of the Gallic provinces [Gaul], but totally omitted by the Greek writers. In summer time, numberless snakes become artificially entwined together, and form rings around their bodies with the viscous slime which exudes from their mouths, and with the foam secreted by them: the name given to this substance is "anguinum." The Druids tell us, that the serpents eject these eggs into the air by their hissing, and that a person must be ready to catch them in a cloak, so as not to let them touch the ground; they say also that he must instantly take to flight on horseback, as the serpents will be sure to pursue him, until some intervening river has placed a barrier between them. The test of its genuineness, they say, is its floating against the current of a stream, even though it be set in gold. But, as it is the way with magicians to be dexterous and cunning in casting a veil about their frauds, they pretend that these eggs can only be taken on a certain day of the moon; as though, forsooth, it depended entirely upon the human will to make the moon and the serpents accord as to the moment of this operation.

I myself, however, have seen one of these eggs: it was round, and about as large as an apple of moderate size; the shell of it was formed of a cartilaginous substance, and it was surrounded with numerous cupules, as it were, resembling those upon the arms of the polypus: it is held in high estimation among the Druids. The possession of it is marvellously vaunted as ensuring success in law-suits, and a favourable reception with princes; a notion which has been so far belied, that a Roman of equestrian rank, a native of the territory of the Vocontii, who, during a trial, had one of these eggs in his bosom, was slain by the late Emperor Tiberius, and for no other reason, that I know of, but because he was in possession of it.

30. The Gallic provinces, too, were pervaded by the magic art, and that even down to a period within memory; for it was the Emperor Tiberius that put down their Druids, and all that tribe of wizards and physicians. But why make further mention of these prohibitions, with reference to an art which has now crossed the very Ocean even, and has penetrated to the void recesses of Nature? At the present day, struck with fascination, Britannia still cultivates this art, and that, with ceremonials so august, that she might almost seem to have been the first to communicate them to the people of Persia. To such a degree are nations throughout the whole world, totally different as they are and quite unknown to one another, in accord upon this one point!

Such being the fact, then, we cannot too highly appreciate the obligation that is due to the Roman people, for having put an end to those monstrous rites, in accordance with which, to murder a man was to do an act of the greatest devoutness, and to eat his flesh was to secure the highest blessings of health.

Tacitus [ca. 55-ca. 120 AD], Annals:

14.30 [on the Roman invasion of the Druid sanctuary of Mona, today’s island of Anglesey, Wales] On the shore stood the opposing army with its dense array of armed warriors, while between the ranks dashed women, in black attire like the Furies, with hair dishevelled, waving brands. All around, the Druids, lifting up their hands to heaven, and pouring forth dreadful imprecations, scared our soldiers by the unfamiliar sight, so that, as if their limbs were paralysed, they stood motionless, and exposed to wounds. Then urged by their general's appeals and mutual encouragements not to quail before a troop of frenzied women, they bore the standards onwards, smote down all resistance, and wrapped the foe in the flames of his own brands. A force was next set over the conquered, and their groves, devoted to inhuman superstitions, were destroyed. They deemed it indeed a duty to cover their altars with the blood of captives and to consult their deities through human entrails.

Tacitus, Histories:

4.54 The Gauls, they remembered, had captured the city [Rome, ca. 390 BC] in former days, but, as the abode of Jupiter was uninjured, the Empire had survived; whereas now the Druids declared, with the prophetic utterances of an idle superstition, that this fatal conflagration was a sign of the anger of heaven, and portended universal empire for the Transalpine nations.

Aelius Lampridius?, Historia Augusta: Life of Alexander Severus:

60.6 Furthermore, as he went to war a Druid prophetess cried out in the Gallic tongue, "Go, but do not hope for victory, and put no trust in your soldiers."

Vopiscus?, Historia Augusta: Life of Numerian:

14. This story my grandfather related to me, having heard it from Diocletian himself. "When Diocletian," he said, "while still serving in a minor post, was stopping at a certain tavern in the land of the Tungri in Gaul, and was making up his daily reckoning with a woman, who was a Druidess, she said to him, 'Diocletian, you are far too greedy and far too stingy,' to which Diocletian replied, it is said, not in earnest, but only in jest, 'I shall be generous enough when I become emperor.' 3 At this the Druidess said, so he related, 'Do not jest, Diocletian, for you will become emperor when you have slain the Boar.' "

Vopiscus? Historia Augusta: Life of Aurelian: 

43.4-5 For he [Asclepiodotus] used to relate that on a certain occasion Aurelian consulted the Druid priestesses in Gaul and inquired of them whether the imperial power would remain with his descendants, but they replied, he related, that none would have a name more illustrious in the commonwealth than the descendants of Claudius. 5 And, in fact, Constantius is now our emperor, a man of Claudius' blood, whose descendants, I ween, will attain to that glory which the Druid priestesses foretold.

Ausonius [ca. 310-395 AD], Commemoratio professorum Burdigalensium:

5.7-10    If report does not lie,
      you were sprung from the stock of the Druids of Bayeux,
and traced your hallowed line
     from the temple of Belenus.

10.22-30 Nor must I leave unmentioned
     the old man Phoebicius,
who, though keeper of Belenus’s temple,
     got no profit thereby.
Yet he, sprung, as rumor goes,
      from the stock of the Druids
of Armorica,
     obtained a chair at Bordeaux
by his son’s help.

Hippolytus of Rome? [ca. 170-ca.236 AD], Refutatio Omnium Haeresium:

1. 25 The Celtic Druids applied themselves thoroughly to the Pythagorean philosophy, being urged to this pursuit by Zamolxis, the slave of Pythagoras, a Thracian by birth, who came to those parts after the death of Pythagoras, and gave them the opportunity of studying the system. And the Celts believe in their Druids as seers and prophets because they can foretell certain events by the Pythagorean reckoning and calculations. We will not pass over the origins of their learning in silence, since some have presumed to make distinct schools of the philosophies of these peoples. Indeed, the Druids also practice the magic arts.

Clement of Alexandria [ca. 150-ca. 210 AD], Stromata:

1.15.70.1 Alexander, in his book On the Pythagorean Symbols, relates that Pythagoras was a pupil of Nazaratus the Assyrian a (some think that he is Ezekiel; but he is not, as will afterwards be shown), and will have it that, in addition to these, Pythagoras was a hearer of the Galatae and the Brahmins.

1.15.71.3. Thus philosophy, a science of the highest utility, flourished in antiquity among foreigners, shedding its light over the nations. And afterwards it came to Greece. First in its ranks were the prophets of the Egyptians; and the Chaldeans among the Assyrians; and the Druids among the Gauls; and the Samanaeans among the Bactrians; and the philosophers of the Celts; and the Magi of the Persians…

Cyril of Alexandria, [ca. 378-444] Contra Iulianum 4.133:

And also those called "prophets" among the Egyptians practiced philosophy - and moreover the Chaldaeans of the Assyrians, the Druids of the Gauls, the Śramanas from among the Persian Bactrians, and not a few from among the Celts, and the Magi among the Persians, and the Gymnosophists among the Indians, and Anacharsis himself among the Scythians, Zamolxis in Thrace, and, they say, some also from the Hyperborian race

Valerius Maximus [writing ca. 35 AD], wrote a collection of historical anecdotes:

2.6.10. Having completed my discussion of this town [Massilia], an old custom of the Gauls should be mentioned: they lend money repayable in the next world, so firm is their belief in the immortality of the spirit.  I would say they are fools, except what these trowser-wearers believe is the same as the doctrine of toga-wearing Pythagoras.