Centaurs are a legendary race of half-man and half-horse creatures. House Caswell includes a centaur in their sigil.
Centaurs supposedly lived in the eastern grasslands of central Essos in the Dawn Age. Archmaester Hagedorn has put forth the theory that these "centaurs" were no more than mounted warriors, as perceived by neighboring tribes who had not yet learned to tame and ride horses. His views have become widely accepted at the Citadel, despite the purported "centaur skeletons" that turn up in grotesqueries from time to time.