Which crusader king was known as Baldwin the Leper?

Baldwin IV was the crusader king known as Baldwin the Leper.

Baldwin IV ruled the Kingdom of Jerusalem from 1174 until his death in 1185. He became king at about thirteen, after the death of his father, Amalric I. His tutor, the historian and archbishop William of Tyre, had noticed signs of leprosy during Baldwin’s childhood; the disease gradually damaged his hands, face, and ability to move.

Despite his illness, Baldwin remained an active monarch. He rode and commanded armies, and in 1177 he helped defeat Saladin at the Battle of Montgisard. His reign was also dominated by arguments among Jerusalem’s nobles and by the problem of succession, since his condition prevented him from marrying and producing an heir.

Baldwin V, the child of his sister Sibylla, was crowned co-king in 1183 and succeeded him after his death. Baldwin II and Baldwin V are therefore easy names to confuse, but neither was the “Leper King.” The title belongs specifically to Baldwin IV of Jerusalem, not to a generic Baldwin associated with the Crusader states.