Humphrey IV of Toron was a leading baron in the Kingdom of Jerusalem. He inherited the Lordship of Toron from his grandfather, Humphrey II, in 1179. He was also heir to the Lordship of Oultrejourdan through his mother, Stephanie of Milly. In 1180, he renounced Toron on his engagement to Isabella, the half-sister of Baldwin IV of Jerusalem. The king, who had suffered from leprosy, allegedly wanted to prevent Humphrey from uniting two large fiefs. Humphrey married Isabella in Kerak Castle in autumn 1183. Saladin, the Ayyubbid sultan of Egypt and Syria, laid siege to Kerak during the wedding, but Baldwin IV and Raymond III of Tripoli relieved the fortress.

Toron, now Tibnin or Tebnine in southern Lebanon, was a major Crusader castle, built in the Lebanon mountains on the road from Tyre to Damascus. The castle was the centre of the Lordship of Toron, a seigneury within the Kingdom of Jerusalem, actually a rear-vassalage of the Principality of Galilee.