The cockatrice was first described in its current form in the late twelfth century.
The Oxford English Dictionary gives a derivation from Old French cocatris, from medieval Latin calcatrix, a translation of the Greek ichneumon, meaning tracker. The twelfth century legend was based on a reference in Pliny's Natural History[1] that the ichneumon lay in wait for the crocodile to open its jaws for the trochilus bird to enter and pick its teeth clean.[2] An extended description of the cockatriz by the 15th-century Spanish traveler in Egypt, Pedro Tafur, makes it clear that the Nile crocodile is intended.[3]
According to Alexander Neckam's De naturis rerum (ca 1180), the cockatrice was supposed to be born from an egg laid by a chicken and incubated by a toad; a snake might be substituted in re-tellings. Cockatrice became seen as synonymous with basilisk when the basiliscus in Bartholomeus Anglicus' De proprietatibus rerum (ca 1260) was translated by John Trevisa as cockatrice (1397).[4] A basilisk, however, is usually depicted without wings.
It is thought that a cock egg would birth a cockatrice, and could be prevented by tossing the yolkless egg over the family house, landing on the other side of the house, without allowing the egg to hit the house.