Aristotle [ca. 350 BCE] (De animalibus, Book 8, 27.2; 9, 2.9; 9, 7.4): [Book 8, 27.2] In Poroselene a road divides the country, on one side of which the weasel is found, and not on the other. [Book 9, 2.9] The serpent is an enemy to the weasel ... for if the weasel and serpent live in the same house they both require the same kind of food... [Book 9, 7.4] The weasel eats the herb rue before it attacks a serpent, for the smell of this herb is obnoxious to serpents. ... The weasel also appears prudent in the way in which it attacks birds, for it kills them in the same manner as wolves kill sheep; it will fight also with serpents, and especially with those that hunt mice; for the weasel pursues the same animals. - [Cresswell translation, 1887]

Ovid [1st century CE] (The Metamorphoses, Book 9, 273-323): The goddess with power over the womb leapt up in consternation, releasing her clasped hands: by releasing the bonds, herself, easing the birth. They say Galanthis laughed at the duped goddess. As she laughed, the heaven-born one, in her anger, caught her by the hair, and dragged her down, and as she tried to lift her body from the ground, she arched her over, and changed her arms into forelegs. Her old energy remained, and the hair on her back did not lose her hair’s previous color: but her former shape was changed to that of a weasel. And because her lying mouth helped in childbirth, she gives birth through her mouth, and frequents my house, as before.’ - [Kline translation]

Pliny the Elder [1st century CE] (Natural History, Book 8, 33; 8, 41):[Book 8, 33] ...the venom of weasels is fatal [to the basilisk]: so fixed is the decree of nature that nothing shall be without its match. They throw the basilisks into weasels' holes, which are easily known by the foulness of the ground, and the weasels kill them by their stench and die themselves at the same time, and nature's battle is accomplished. [Book 8, 41] ...the weasel cures itself with rue when it has had a fight with mice in hunting them. - [Rackham translation]

Gaius Julius Solinus [3rd century CE] (De mirabilibus mundi / Polyhistor, Chapter 27.53): ...the basilisk is defeated by weasels, which men in those parts stuff into the caverns in which it takes shelter. - [Arwen Apps translation translation, 2011]

Isidore of Seville [7th century CE] (Etymologies, Book 12, 3:3; 12, 4.7; 17, 11.8): [Book 12, 3.3] The weasel [mustela] is so named as if it were a long mouse [mus], for a dart [telum] is so named due to its length. This animal, by its nature, practices deceit in the houses where it nurses its pups, and it moves and changes its dwelling. It hunts snakes and mice. There are two kinds of weasels; one, which the Greeks call nyfítsa, lives in the wild and is larger, while the other wanders into houses. Those people who suppose that the weasel conceives through its mouth and bears its young through its ear are mistaken. [Book 12, 4.7] However, the basilisk may be overcome by weasels. For this reason people take weasels into caves where the basilisk lies hidden; and as the basilisk takes flight at the sight, the weasel chases it down and kills it. [Book 17, 11.8] Weasels show that rue fends off poisons, because they protect themselves by eating it when they fight with snakes. - [Barney, Lewis, et. al. translation]

Gerald of Wales [c. 1146 – c. 1223] (Topographia Hibernica, chapter 22): There are here a vast number of weasels, but they are very small, and are of a reddish color. This little animal has more spirit than body, and its courage supplying the deficiency of its strength, with a great heart actuating a slender frame, it is vindictive and relentless in its wrath, however it may hide it for a time. When injured it dissembles its resentment and defers its revenge; it is the tyrant of the larger sorts of mice, and commits great ravages by gnawing clothes. It preys also on hares and rabbits, nor does it shrink from engaging in single combat with the snake, in which conflict, often pretending to run away, it betakes itself to some mound of earth which it has noted before, and having a hole through the middle as well as one perforated above in the form of a cross. The snake gliding after it, and being entangled in the narrow passage without the power of wriggling out, the weasel darts upon it from the upper orifice with its natural agility, and seizes it with its teeth, without suffering any injury. Thus, by an innate impulse and ingenuity, not to call it a wonderful instinct, the weasel, avoiding its terrible enemy's venomous head, triumphs over it more by art than by prowess. ... The weasel also, when its young are dying from any hurt, recovers and restores them to life by the use of a yellow flower. We are told by persons who have witnessed the fact, having put the whelp to death to make the experiment, that the weasel brought the flower in its mouth, and first applied it to the wound, and then to the mouth, nostrils, and other orifices of the little animal, that it might inhale the odor, by which, through the efficacious touch of the plant, breath was restored, though life seemed extinct, some slight and imperceptible vestiges of it only having remained. Moreover, as death destroys every thing else by its mere glance, such is the weasel to the basilisk. - [Forester translation, 1863, chapter 22]

Aberdeen Bestiary [circa 1200 CE] (folio 23v): The weasel is called mustela, 'a long mouse', so to speak, for theon [telos] in Greek means 'long'. It is cunning by nature; when it has produced its offspring in its nest, it carries them from place to place, settling them in a series of different locations. It hunts snakes and mice. There are two kinds of weasel. One, of very different size from the other, lives in the forest. The Greeks call these ictidas; the other roams around in houses. Some say that weasels conceive through the ear and give birth through the mouth; others say, on the contrary, that they conceive through the mouth and give birth through the ear; it is said, also, that they are skilled in healing, so that if by chance their young are killed, and their parents succeed in finding them, they can bring their offspring back to life. Weasels signify the not inconsiderable number of people who listen willingly enough to the seed of the divine word but, caught up in their love of worldly things, ignore it and take no account of what they have heard.

Thomas of Cantimpré [circa 1230-1245 CE] (Liber de natura rerum, Quadrupeds 4. 47. 4.49, 4.77): [Thomas describes the weasel under the names mustella, gali, and guesseles.] Gali is a transliteration into Latin of an Arabic word found in Michael Scot's translation of Aristotle. Guesseles is a transliteration of the Flemish name wesel. All describe the same anima (Cipriani, chapter 4)] [Quadrupeds 4.47] The gali, as Aristotle says, is an animal with much boldness. It fights with snakes, and when it has defeated them, it eats them, and soon afterwards it eats [the herb] rue which is a cure for snake venom. The main reason why it fights with snakes is that snakes live on the flesh of mice, and the gali itself likes to eat mice. This animal enters its burrows from the north or from the south, so as not to be tired by the wind against it. [Quadrupeds 4.49] The guessules, or roserula as it is commonly called, is an animal that often lives around water. This animal is bigger than a weasel and smaller than a squirrel. It is brown on the back, white on the belly. This animal makes dwellings in the earth. It produces dung very fragrant like musk in smell, but unequaled in strength of smell. And this is a wonder in the beast: in one place it piles up the bad dung, where it seems that it does not bother men, but lays down its good dung where all can receive it. It flees from the sight of men; by which it is hinted to us, that in doing good we avoid the sight and praise of men. Weasel is named mustela, as if 'a long mouse'; For 'telos' in Greek is long in Latin. For there are two kinds of weasels, as Isidore says: the larger one is called ictide, it is red in the belly, and red in the back. This beast is cunning in his wits. It cares for the cubs diligently and often moves them from place to place so that they may not be found. [Quadrupeds 4.77] As the Experimentator says, the weasel sleeps very long and very deeply. It inhabits rocks and caves. When it wants to fight with a snake, it defends itself with wild rue [herb]. Accordingly they are said to be expert in all the arts of medicine, so that, if they find their offspring dead, they make them naturally recuperate by means of a herb. it chases rats and snakes. In the island of Poroselena, weasels do not live, as Pliny says, but if they are carried there, they die. Into Boetia also they flee immediately, and this in that Boetia which is called Lebadia. Now Solinus says that the weasel kills the basilisk, which, however, kills men with a mere sight, but with its breath kills the other living creatures of the earth. As the Liber Kyrannidarum says: If a weasel is cooked in olive oil until its body is dissolved and strained through a cloth, the oil is effective against arthritis and stiff nerves and phlegmon of the feet and all rheumatism and scrofula. His left testicle, tied around the neck of a hen, causes it to lay an egg. If blood of the weasel is given to the epileptic, he is cured. Its gall is a remedy against the asp; the rest is poison, as Pliny says. On the contrary, Isidore says that those who say that a weasel conceives with the mouth and gives birth through the ear are of false opinion. - [Badke translation/paraphrase]

Bartholomaeus Anglicus [13th century CE] (Liber de proprietatibus rerum, Book18.9; 18.73): [Book 18.9] Also Aristotle lib. 8. telleth, that the wéesell sighteth against Serpents, & armeth himselfe with eating of Rewe, and fighteth namely against Serpents yt eate Mice. For the Wéesell hunteth and eateth Mice. [Book 18.73] The Wesell is called Mustela, and is so called, as it were a long mouse, as Isi[dore] saith li. 12. for long is called Telon in Gréek, this beast hath a guileful wit, and nourisheth hir Kittons in houses, & beareth them from place to place, and chaungeth place and dwelling, for hir neast should not be found. The Wesell pursueth and chaseth Serpents, and hateth and eateth mice. And of Wesels is double manner kinde, one dwelleth in woodes, and is more than other. And the Gréeks call it Locidas, and the other goeth about in houses. And their opinion is false, that means, that Wesells conceive at the mouth, & kitneth at the eare. as Isid[ore] saith li. 12. The wesell is enemie to Sparowes, and lyeth in awaite for them and other small birdes, and swalloweth up their egges: and if the Wesels kittens fall by any hap in chins or in pits, and be hurt or dead, the Wesell heleth them with a certain hearb, & reareth them from death to life, as Pli[ny] saieth, and eateth Rewe, and bawmeth hir selfe with juyce thereof, and réeseth then on the Cockatrice, and assaileth and slaieth him without any dred boldly, as Pli[ny] saith li. 8. ca. 22. There it is said, that the vertue of wesells is death to the Cockatrice, for God and kinde will, that nothing be without a help: the wesell knoweth soone of the Cockatrice, and goeth into his den, and slaieth him there, and is a beast that sléepeth much, and wexeth fat with sléepe, as the mice doe, that are called Glires, as he saith. Also li. 29. ca. 1. he saith, that ye wesell is of double kind, tame & wilde, & either hath gall yt helpeth much against Adders: for their previe chose stinketh right foule, & stinking things is contrary to adders & serpents, and we meane, that their flesh helpeth against venim. A wesel burnt to ashes, is helthfully done in medicine, & helpeth against Litargie, ye sléeping evill, & so if a man fall into Litargy the sléeping evill, by venimme of an Adder, the ashes of a wesel tempered with drops of water, dissolveth and destroyeth ye strength and might of ye sléepe, as he saith: & ther it is said, ye pouder helpeth against festers, for kind yt is mother of all, gendreth nothing without great cause, as it is sayd. Li. 8. Arist[otle] saith, yt the wesell fighteth against serpents, for either eate mice, & is a swift beast of moving, & pliant of body, & full slipper & unstable, & wise in smell, & hath a red & a white wombe, & changeth coulour: for in some countries somtime of ye yeare all his skinne is white, except the tayle. His biting is malitious and venemous, and his urine stinketh as the urine of the mouse. - [Batman]