Balthazar was one of the three magi ("wise men" - most likely meaning priests) who brought gifts to anoint Jesus Christ upon his birth. The wise men only appear in the book of Matthew and are not named or even numbered. Later Christian tradition fleshed out their identities and made them kings. Balthazar, whose name means "lord of the treasures", was king of Arabia. The Venerable Bede claimed he was the son of Shem, one of Noah’s sons. Bede also believed that Balthazar, the youngest of the magi, was black, emphasizing the idea that Christ had come to save all of mankind.

Balthazar brought myrrh, the gift for a prophet in Jewish tradition. Myrrh’s use in embalming was thought to prefigure the death of Christ.