William IV was the Lord of Montpellier from 1058 until his death in 1068. He was the son of William III

William III of Montpellier

William III was the Lord of Montpellier from 1025 until his death in 1058. He was the son of William II and husband of Beliardis. His son and successor was William IV. He is the last of the "shadowy" Guilhems, none of whose charters are conserved in the family cartulary, the Liber instrumentorum...

 and Beliardis. He was married to Ermengarde, daughter of Raymond I, Count of Melgueil. He is the first of his dynasty with charters preserved in the family cartulary, the Liber instrumentorum memorialium

Liber instrumentorum memorialium

The Liber instrumentorum memorialium is the surviving cartulary of the Lords of Montpellier, the Guilhems , and an important source for their history. It was compiled in the early thirteenth century, under the patronage of William VIII, whose lordship is extensively catalogued in it. Its earliest...

. They record agreements concerning some local castles in 1059. He was succeeded by his son, William V

William V of Montpellier

William V was the Lord of Montpellier from an early age until his death. He was the son of Bernard William IV.Soon after his father's death, his mother, Ermengarde, quit Montpellier to marry the Lord of Anduze...

.