Bayard is a magical bay horse in the legends derived from the medieval chansons de geste. These texts, especially that of The Four Sons of Aymon, attribute to him magical qualities and a supernatural origin. He is known for his strength and intelligence, and possesses the supernatural ability to adjust his size to his riders.

The chanson de geste is a medieval narrative, a type of epic poem that appears at the dawn of French literature. The earliest known poems of this genre date from the late 11th and early 12th centuries, shortly before the emergence of the lyric poetry of the troubadours and trouvères, and the earliest verse romances. They reached their highest point of acceptance in the period 1150–1250.