Aristotle [ca. 350 BCE] (De animalibus, Book 5, 27.1; Book 8, 3.4): [Book 5, 27.1] The marine turtles deposit their eggs in the earth like domestic birds, and cover them up with earth and sit upon them during the night. They produce a great many eggs, as many as a hundred. [Book 8, 3.4 ] The marine turtles live upon shell-fish, for which purpose they have a very powerful mouth; for if any of them take a stone or anything else, they break and eat it. This animal leaves the water and eats grass. They often suffer and perish, when they are dried up as they float on the surface, for they are not able to dive readily. - [Cresswell translation, 1887]

Pliny the Elder [1st century CE] (Natural History, Book 9, 12): The Indian Ocean produces turtles of size that the natives roof dwelling-houses with the expanse of a single shell, and use them as boats in sailing, especially among the islands of the Red Sea. They are caught in a number of ways, but chiefly as they rise to the surface of the sea when the weather in the morning attracts them, and float across the calm waters with the whole of their backs projecting, and this pleasure of breathing freely cheats them into self-forgetfulness so much that their hide gets dried up by the heat and they are unable to dive, and go on floating against their will, an opportune prey for their hunters. They also say that turtles come ashore at night to graze and after gorging greedily grow languid and when they have gone back in the morning doze off to sleep on the surface of the water; that this is disclosed by the noise of their snoring; and that then the natives swim quietly up to them, three men to one turtle, and two turn it over on its back while the third throws a noose over it as it lies, and so it is dragged ashore by more men hauling from the beach. Turtles are caught without any difficulty in the Phoenician Sea; and at a regular period of the year they come of their own accord into the river Eleutherus in a straggling multitude. The turtle has no teeth, but the edges of the beak are sharp on the upper side, and the mouth closing the lower jaw lie a box is so hard that they can crush stones. They live on shell-fish in the sea and on plants when they come ashore. They bear eggs like birds' eggs numbering up to 100 at a time; these they bury in the ground somewhere ashore, cover them with earth rammed down and leveled with their chests, and sleep on them at night. They hatch the young in the space of a year. Some people think that they cherish their eggs by gazing at them with their eyes; and that the females refuse to couple till the male places a wisp of straw on one as she turns away from him. The Cavemen have horned turtles with broad horns twisted inward like those of a lyre but movable, which they use as oars to aid themselves in swimming; the name for this horn is chelium; it is of tortoise shell of exceptional quality, but it is seldom seen, as the very sharp rocks frighten the Turtle-eater tribe, while the Cavemen, on whose coasts the turtles swim, worship them as sacred. - [Rackham translation]

Thomas of Cantimpré [circa 1200-1272 CE] (Liber de natura rerum, Marine monsters 6.5, 6.48, 6.53, 6.58): {Thomas describes the sea turtle under the names barchora, testudines, tortuca and zytiron.] [Marine monsters 6.5] Barchora, as Aristotle says, is a marine animal that eats small fish. The mouth of this animal is stronger than any other animal's mouth, for if it takes a stone in its mouth, it will break it. This animal sometimes goes out to the bank and grazes on the grass. It must return to the water and submerge itself in the water, lest the skin of its back be dried by the sun, and it be unable to dive properly. This animal is caught by fishermen by means of small fish, which they throw into the sea, sewn alive with thread. But the fishes, not being able to escape, but floating at the same time, are exposed to the bites of the aforesaid animal. But the animal itself is caught while trying to swallow one fish after another. [Marine monsters 6.48] The Indian sea has turtles (testudines), of which men make capacious shelters for themselves, and sail among the islands of the Red Sea in these boats, as Pliny says. These turtles are caught in wonderful ways, but especially when they are floating in the very top of the ocean with their whole back above the water, they float so calmly that the pleasure of breathing freely makes them forget themselves to such an extent that they cannot sink because their skin has been dried by the heat of the sun, and they float to the ready hands of hunters. They go out of the water to feed at night, and when they are greedily satisfied, return in the morning, they fall asleep deep in the water. Then three men swim toward them and two of them turn the turn them on their backs, and a third throws a noose over their backs, and thus they are dragged to the land by several others. In this monster there are no teeth, but the edges of the beak are sharp, and the upper part is closed by the lower part just like a box. The hardness of the mouth is so great that it crushes even stones. They come together like cattle. But the female does not willingly or lightly suffer intercourse, until the male turns her and places a straw in her mouth. Having come out on the land, they lay goose-like eggs to the number of hundreds, and bury them outside the water with their chest, and they incubate at night. They bring up their offspring at an annual interval. Some say that they care for the eggs only by gazing at them with their eyes; and this is very wonderful, but the matter is hidden. [Marine monsters 6.53] The sea turtle [tortuca] is a huge monster and excessively strong. It is shaped like a terrestrial tortoise, but it is infinitely larger than its size: for its length is eight cubits and its breadth four. It has a triangular shell like a shield, but much larger, being five cubits. Its legs are long, its claws are large, and its toes are larger than those of lions. It thrives wonderfully with strength and audacity, since it is not afraid to attack three men. It is frustrated in its strength if you can turn it on its back to the ground. For it rises with difficulty when it is turned on its back, and this because of the width of the shield, by which such a beast is enclosed on the back: with this shield it is covered against arrows; and it is a triangular shield. [Marine monsters 6.53] Zytiron is a sea monster, which the common people call 'the warrior of the sea' and it is huge and very strong. It is said to have a form of this kind: in the front part it takes the form of an armed soldier, and the head is like a metal helmet of wrinkled and hard skin, and very firm. From its neck hangs a shield, long and broad and large, and hollow inside, so that with it the monster can defend itself against the blows of combatants. A certain vein and very strong nerves extend from its neck and from its vertebrae to its shoulder, and from these the aforesaid shield hangs on its shoulder. Also the shield itself is triangular in shape, so strong in hardness and strength that it can hardly ever be penetrated by an arrow. Its arms are exceedingly strong, and its hands are cloven, with which it strikes so violently, that a man tries in vain to be able to sustain the blows without the greatest hazard. Hence it can only with difficulty be taken by a man. And if it is caught, it can hardly be killed except with hammers. The race of this animal seems to imitate the discord of the human race, which certainly stirs up wars among themselves; and they make such a disturbance of the sea in fighting, that in the place of the fighting a certain storm seems to arise. These monsters are found in the British seas. - [Badke translation/paraphrase]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book18.107): Arist[otle] lib. 8. speaketh of the sea Tortuse and sayth, that he eateth all thing, and his mouth, is stronger than any other waste mouth, for if he take a stone in his mouth, hée breaketh it, and he commeth out of the water to the brinke, & eateth the grasse and hearbes, and when he tourneth againe to the water, he goeth up & swimmeth, so that his backe is drye with the Sunne, for it is not easie to him to bée déepe in water. - [Batman]