Named by Isolt Sayre after the great horned river serpent that has a jewel set into its forehead; Horned Serpent house is sometimes considered to represent the mind of a witch or wizard. It is also said that Horned Serpent favours scholars.
A legend exists concerning the founder of Ilvermorny School of Witchcraft and Wizardry, Isolt Sayre, and a Horned Serpent.
Fantastic Beasts and Where to Find Them
by J.K. Rowling