Walter IV, Count of Brienne

Walter IV the Great of Brienne (French: Gauthier IV le Grand de Brienne (1205–1244) was Count of Brienne 1205–1244. He was the son of Walter III of Brienne and Elvira (Albiria, Albina, Blanche, Mary) of Lecce. Around the time of his birth, his father lost his bid for the Sicilian throne and died in prison. His inheritance of the Principality of Taranto and the County of Lecce was confiscated.

While a teenager, Walter was sent to Outremer where his uncle John of Brienne was the ruler of Jerusalem. In 1221 John gave him the County of Jaffa and Ascalon, and arranged a marriage with Marie de Lusignan (before March, 1215 – ca 1252 or 1254), daughter of Hugh I of Cyprus, in 1233.

Even after his uncle had been forced out of the Kingdom by Frederick II, Walter remained one of the most important lords of the Kingdom of Jerusalem. He was commander of the Crusader army that marched against the forces of As-Salih Ayyub in 1244. Against the advice of al-Mansur of Homs, his Syrian ally, Walter insisted on taking the offensive, rather than fortifying his camp and awaiting the retreat of the Khwarezmians. In the disastrous Battle of La Forbie, the Crusader-Syrian forces were nearly annihilated. Walter was captured, tortured before the walls of Jaffa, and ultimately turned over to the Egyptians after the Khwarezmian defeat before Homs in 1246. He was imprisoned in Cairo and murdered by merchants whose caravans he had robbed, with the sultan's consent.

He was succeeded by his elder son John, who died childless. His younger son Hugh of Brienne settled in Southern Italy and became a partisan of Charles of Anjou, who returned to him the family's county of Lecce.