At the age of fourteen, Alexander the Great successfully tamed a horse called Bucephalus, which no man had been able to approach, mount, or bridle. Because of a prophecy that whoever tamed this wild stallion would conquer the world, this event is key to the Alexander legend, foreshadowing his eventual conquest of much of the known world.
The illuminator depicted Alexander in fancy court dress, with his pointy shoes revealing his royal status. The text describes Bucephalus as having the mane and tail of a lion, but the artist chose to show the beast as a sturdy war-horse. The young Alexander calmly strokes the beast's nose while his father King Philip watches from the far right.