The son of William Longsword of Montferrat and Sibyl, daughter of King Amalric of Jerusalem, co-ruler with his uncle King Baldwin IV (1183-1185) and sole king until his premature death (1185-1186).
Born in the winter of 1177-1178, for most of his short life the young Baldwin V was a pawn in factional struggles during the last days of the kingdom of Jerusalem before its overthrow by Saladin in 1187. By 1178, Baldwin IV had designated his sister Sibyl and her family as heirs apparent. In 1183, he named Sibyl’s second husband, Guy of Lusignan, as regent, but then removed him and had the child Baldwin V crowned as an indication that Guy had been barred from the succession. Before Baldwin IV died (1185), he named Count Raymond III of Tripoli as regent for Baldwin V, again to prevent Guy from claiming authority over his stepson. However, Baldwin V’s unexpected death in 1186 again threw open the question of the succession.