Alfonso's father died when he was two years old and he remained under the guardianship of his cousin, William Jordan, Count of Cerdagne, until he was five. He was then taken to Europe, where his half-brother Bertrand had given him the county of Rouergue. Upon Bertrand's death in 1112, Alfonso succeeded to the county of Toulouse and marquisate of Provence. In 1114, Duke William IX of Aquitaine, who claimed Toulouse by right of his wife Philippa, daughter of Count William IV, invaded the county and conquered it. Alfonso recovered a part in 1119, but he was not in full control until 1123. When at last successful, he was excommunicated by Pope Callixtus II for having expelled the monks of Saint-Gilles, who had aided his enemies.