Bertrand was the eldest son of Raymond IV of Toulouse, and had ruled Toulouse since Raymond left on the First Crusade in 1095. He was, between 1098 and 1100, dispossessed by his cousin Philippa and her husband Duke William IX of Aquitaine, who marched into Toulouse and captured it. Later they mortgaged it back to Bertrand in 1100 to fund Duke William's expedition to the Holy Land. Bertrand officially became count of Toulouse when Raymond died in 1105, and in 1108 he headed to Tripoli to take control there as well. He deposed Raymond's nephew William-Jordan as nominal count of Tripoli in 1109, and with Baldwin I, king of Jerusalem, and a fleet of Genoese ships he captured Tripoli on 12 July.
Bertrand ruled in Tripoli until his death in 1112. He was succeeded by his son Pons in Tripoli, and by his brother Alphonse-Jordan in Toulouse - although Toulouse was at that point again lost to Philippa and William.
- Asbridge, Thomas S. (2000). The Creation of the Principality of Antioch, 1098-1130. The Boydell Press.
- Bouchard, Constance Brittain (1987). Sword, Miter, and Cloister: Nobility and the Church in Burgundy, 980–1198. Cornell University Press.
- Venning, Timothy (2015). A Chronology of the Crusades. Routledge.
- William of Puylaurens (2003). The Chronicle of William of Puylaurens: The Albigensian Crusade and its Aftermath. Translated by Sibley, W.A.; Sibley, M.D. The Boydell Press.
| Count of Toulouse
| Count of Tripoli