Baldwin IV., the son of Amalric I. by his first wife Agnes, ruled in Jerusalem from 1174 to 1183, when he had his nephew Baldwin crowned in his stead. Educated by William of Tyre, Baldwin IV. came to the throne at the early age of thirteen; and thus the kingdom came under the regency of Raymund II. of Tripoli. Happily for the kingdom whose king was a child and a leper, the attention of Saladin was distracted for several years by an attempt to wrest from the sons of Nureddin the inheritance of their father - an attempt partially successful in 1174, but only finally realized in 1183. The problems of the reign of Baldwin IV. may be said to have been two - his sister Sibylla and the fiery Raynald of Chatillon, once prince of Antioch through marriage to Constance (1153-1159), then a captive for many years in the hand of the Mahommedans, and since 1176 lord of Krak (Kerak), to the east of the Dead Sea. Sibylla was the heiress of the kingdom; the problem of her marriage was important. Married first to William of Montferrat, to whom she bore a son, Baldwin, she was again married in 1180 to Guy of Lusignan; and dissensions between Sibylla and her husband on the one side, and Baldwin IV. on the other, troubled the latter years of his reign.
Meanwhile Raynald of Krak took advantage of the position of his fortress, which lay on the great route of trade from Damascus and Egypt, to plunder the caravans (1182), and thus helped to precipitate the inevitable attack by Saladin. When the attack came, Guy of Lusignan was made regent by Baldwin IV., but he declined battle and he was consequently deposed both from his regency and from his right of succession, while Sibylla's son by her first husband was crowned king as Baldwin V. in 1183. For a time Baldwin IV. still continued to be active; but in 1184 he handed over the regency to Raymund of Tripoli, and in 1185 he died.
The narrative of William of Tyre concludes with Baldwin IV.'s transfer of the regency to Raymund of Tripoli. R. Röhricht describes the reign of Baldwin IV., Geschichte des Königreichs Jerusalem (Innsbruck, 1898), C. xix.-xxi.