Aristotle [ca. 350 BCE] (De animalibus, Book 6, 6.2; 9, 2.4; 9, 2.6; 9, 2.9; 9, 21.3): [Book 6, 6.2] The raven produces not only two, but, as they say, many eggs, which she sits upon for about twenty days. She also turns out some of her young ones. [Book 9, 2.4] The kite and raven are enemies; for the kite, from the superiority of its claws and flight, can take from the raven anything it may have caught, so that their food is the cause of their enmity also. [Book 9, 2.6] The raven is an enemy to the bull and ass, for it flies round them and strikes their eyes. [Book 9, 2.9] The raven and the fox are friendly, for the raven also attacks the aesalon [merlin], and so they help each other in the attack. [Book 9, 21.3] The ravens in small districts, and where they have not food enough, are found only in pairs; and as soon as their young birds are able to fly, the old birds first of all turn them out of the nest, and then drive them from the place. The raven lays four or five eggs. When the hired soldiers of Medias perished in Pharsalus, Athens and the Peloponnesus were deserted by the ravens, as if they had some means of communication with each other. - [Cresswell translation, 1887]

Ovid [1st century CE] (The Metamorphoses, Book 2, 531): ... at the same time that your wings, Corvus, croaking Raven, were suddenly changed to black, though they were white before. He was once a bird with silver-white plumage, equal to the spotless doves, not inferior to the geese, those Saviour of the Capitol with their watchful cries, or the swan, the lover of rivers. His speech condemned him. Because of his ready speech he, who was once snow white, was now white’s opposite. - [Kline translation]

Pliny the Elder [1st century CE] (Natural History, Book 8, 41; 10, 15; 10, 60; 10, 95): [Book 8, 41] When a raven has killed a chameleon lizard, which is noxious even to its conqueror, it stanches the poisonous infection with bay-leaves. [Book 10, 14]...whereas all the other birds of the same class [as crows] drive their chicks out of the nests and compel them to fly, as also do ravens. These not only feed on flesh themselves too, but also drive away their chicks when strong to a considerable distance. Consequently in small villages there are not more than two pairs of ravens, and in fact in the neighborhood of Crannon in Thessaly there is one pair permanently in each place; the parents retire to make room for their offspring. There are certain points of difference between this bird and the one mentioned above [crow]. Ravens breed before midsummer, also they have 60 days of ill health, principally owing to thirst, before the figs ripen in the autumn; whereas the crow is seized with sickness from that day onward. Ravens produce broods of five at most. There is a popular belief that they lay eggs, or else mate, with the beak (and that consequently if women with child eat a raven's egg they bear the infant through the mouth, and that altogether they have a difficult delivery if raven's eggs are brought into the house); but Aristotle says that this is not true of the raven, any more indeed than it is of the ibis in Egypt, but that the billing in question (which is often noticed) is a form of kissing, like that which takes place between pigeons. Ravens seem to be the only birds that have an understanding of the meanings that they convey in auspices; for when the guests of Medus were murdered, all the ravens in the Peloponnese and Attica flew away. It is a specially bad omen when they gulp down their croak as if they were choking. [Book 10, 60] Certain persons have thought it worth recording that a raven was seen during a drought dropping stones into a monumental urn in which some rain water still remained but so that the bird was unable to reach it; in this way as it was afraid to go down into the urn, the bird by piling up stones in the manner described raised the water high enough to supply itself with a drink. [Book 10, 95] There are quarrels between ... the raven and the golden oriole when searching for one another's eggs by night; similarly between the raven and the kite when the former snatches the latter's food before he can get it... There is a small bird called the aesalon [merlin] that breaks a raven's eggs, whose chicks are preyed upon by foxes, and it retaliates by pecking the fox cubs and the vixen herself; when the ravens see this they come to their aid against the aesalon as against a common foe. - [Rackham translation]

Aelianus [170-230 CE] (On the Characteristics of Animals, Book 1.47-48; 2.48-49; 2.51): [Book 1.47] All through the summer the raven is afflicted with a parching thirst, and with his croaking (so they say) declares his punishment. And the reason they give is this. Being a servant he was sent out by Apollo to draw water. He came to a field of corn, tall but still green, and waited till it should ripen, as he wanted to nibble the wheat: to his master's orders he paid no heed. On that account in the driest season of the year he is punished with thirst. This looks like a fable, but let me repeat it out of reverence for the god. [Book 1.48] The Raven, they say, is a sacred bird and attends upon Apollo: that is why men agree that it is also of use in divination, and those who understand the positions of birds, their cries, and their flight whether on the left or on the right hand, are able to divine by its croaking. I am also informed that raven's eggs turn the hair black. And it is essential for anyone who is dyeing his hair to keep olive oil in his mouth and his lips closed. Otherwise his teeth also turn black along with his hair, and they are hardly to be washed white again. [Book 2.48] The Ravens in Egypt which live beside the Nile at first appear to be begging of the people sailing on the river, soliciting to be given something. And if they are given, they stop begging; but if their solicitations fail, they fly in a mass and perch on the sail-yards of the ship and proceed to eat the ropes and to cut the cords. But the ravens of Libya, when men through fear of thirst draw water and fill their vessels and place them on the roof so that the fresh air may keep the water from putrefying, the ravens, I say, help themselves to drink by bending over and inserting their beaks as far as they will go. And when the water gets too low they gather pebbles in their mouth and claws and drop them into the earthenware vessel. Now the pebbles are borne down by their weight and sink, while the water owing to their pressure rises. So the ravens by a most ingenious contrivance get their drink; they know by some mysterious instinct that one space will not contain two bodies. [Book 2.49] Aristotle asserts that ravens know the difference between a prosperous and a barren country, and in one that produces all things in plenty they move about in flocks and great numbers, but in a barren and unfruitful country in pairs. As to their young ones, when fully grown, every raven banishes them from its nest. For that reason they seek their food for themselves and neglect to care for their parents. [Book 2.51] Of the Raven you might say that it has a spirit no less daring than the eagle, for it even attacks animals, and not the smallest either, but asses and bulls. It settles on their neck and pecks them, and in many cases it actually gouges out their eyes. And it fights with that vigorous bird the merlin, and whenever it sees it fighting with a fox, it comes to the fox's rescue, for it is on friendly terms with the animal. The raven must really be the most clamorous of birds and have the largest variety of tones, for it can be taught to speak like a human being. For playful moods it has one voice, for serious moods another, and if it is delivering answers from the gods, then its voice assumes a devout and prophetic tone. - [Scholfield translation]

Gaius Julius Solinus [3rd century CE] (De mirabilibus mundi / Polyhistor, Chapter 40.24): [The chameleon is poisonous to ravens. If it is killed by a raven, it destroys the very conqueror which has killed it, for if the bird consumes even a little of it, it immediately perishes. But the raven has a defense, as Nature has stretched forth its hand with a cure. When the raven understands itself to be afflicted, it eats a laurel leaf, and is restored to health. - [Arwen Apps translation, 2011]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 7:43): The raven [corvus], or corax, takes its name from the sound of its throat, because it croaks [coracinare] with its voice. It is said that this bird does not fully provide food for the young it has produced until it recognizes in them a similarity to its own color through the blackness of their feathers, but after it sees that they are horrible of plumage it nourishes them more abundantly, as completely acknowledged offspring. This bird seeks the eyes of a corpse before any other part. - [Barney, Lewis, et. al. translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Bird 5.31): A raven [corvus], as Isidore says, is a bird of black color, so called from the sound of its voice. For it does not knows how to say anything but: tomorrow, tomorrow [cras, cras]. The female lays the eggs and the male brings her food. As Augustine says, the raven does not feed its chicks until it sees their feathers turn black like its own. And so they are forced to remain for seven days without any food, but on the seventh day they turn black. Ravens throw some chicks out of their nests because they are tired of feeding them. ... During the reign of Tiberius, a young raven flew in the morning from the highest tower. Having been entrusted with the work of the master, and having been accustomed to speak early in the morning, flew towards the Tiberium and soon saluted the Roman people as they passed by. It was killed one day, because of envy, when it was returning to the workshop. And without delay, when this was heard in the forum, the people mourned, and, having killed his murderer in revenge, every person of the Roman people celebrated a raven funeral as great as if one of the princes was seen dead. It has also been found of ravens, that if they find water in some deep place, and because of the shortness of their necks they can not reach it at all, they at once throw pebbles into the water, until the water rises so high that they can touch it with their beaks, and satisfy their thirst. Ravens breed before the solstice. The eggs hatch in sixty days. And it lives for many years, and so does every kind of raven. Ravens are said to become pregnant if they happen to eat a raven's egg. As the Experimentator says, the females of ravens lay their eggs in the sun, and the males give them food. A raven never hatches only two chicks, but several. The raven is loud and makes different voices, namely 631, as Fulgentius says. Sometimes they meet while flying. The raven eats the owl's eggs by day, and the owl the raven's eggs by night; but the raven is stronger by day, the owl by night. There is a certain race of ravens in the East, which fight with the ass and the bull. For while they are fleeing, the raven flies over them and attacks their eyes with a rush, and when it can, it strikes the fleeing animal in the eyes with its beak, and thus blinding them renders them useless to their masters; and in consequence they were killed. Thus the wicked bird overcomes the strong animals; and a wicked woman casts down strong men. The raven by nature loves the fox, and therefore helps him against the bird called asalon, because the asalon is the enemy of the raven. - [Badke translation/paraphrase]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book12.10): The Raven is called Corvus of Corax also, and hath that name of the sowne of the throte, as IIsido[re] sayth. The Raven beholdeth the mouth of hir birds, when they yane. But she giveth them no meate ere she know and sée the likenesse of hir owne blacknesse, and of hir owne colour and fethers. And when they begin to wexe blacke, then afterward she feedeth them wt all hir might & strength, as Isidore saith. It is sayd that ravens birdes be fed with deaw of heaven all the time that they have no blacke feathers by benefite of age: for all ye time they be not fed with their usuall meate, which is carren or other stinking things, but with benefit of the deaw of heven, as Austen saith. And ye ravens in dead carrens, goe into the privie places with in as Isid[ore] saith, and is a crieng fowle, and hath divers sowne and voice: for among fowles, onely the Raven hath 64. changings of voyce, as Fulgentius saith: and is guilefull bird, and taketh away things theevishly, and layeth and hydeth them in privie places. Also he is an uncleane bird, and sitteth upon carrens, and asketh and taketh meate of venemous and uncleane things, and as Divinours meane, the Raven hath a manner vertue of meaning and betokening of divination. And therefore, among Nations, the Raven among foules was hallowed to Appollo, as Marcius saith. Aristotle li. 6. speaking of the Raven saith, that onely the female sitteth on broode twentye dayes on the egges, and the male bringeth to hir meate, and they have manie byrdes, and sitteth on broode twentye dayes, and for they be many, they throw away some of their birds: For fowles, which have many birds throwe awaye some of them. Also li. 8. he sayth, that the blacke raven fighteth with the Asse and with the Bul, and flieth upon them, and grieveth them, and smiteth with the bill, and smiteth out theyr eyen. Also there it is sayd, that the blacke Raven is friend to the Foxe: and therfore he fighteth with the Brocke or Badger, and with other small beastes, to helpe the Foxe. Also ther it is sayd, that ravens fight stronglye, and smite together with theyr weapons, that he bills, clees and wings: and be that is overcome, is obedient to the Conquerour. Huc usque Aristotle Also onely the Raven layeth egges, and bréedeth in the middle heate of summer against kind of other fowles. Ther of it is sayd, that the raven laieth egges, and bréedeth in the middle heate of the summer, nigh to ripe fruite. - [Batman]