Luckily for the Buyids, Mardavij was assassinated shortly thereafter in 935, which caused chaos in the Ziyarid territories, a perfect situation for the Buyid brothers; Ali and Ahmad conquered Khuzistan, while Hasan captured the Ziyarid capital of Isfahan, and, in 943, captured Rey, which became his capital, thus conquering all of Jibal. In 945, Ahmad entered Iraq and made the Abbasid Caliph his vassal, at the same time receiving the laqab "Mu'izz ad-Dawla" ("Fortifier of the State"), while 'Ali was given the laqab "Imād al-Dawla" ("Support of the State"), and Hasan was given the laqab "Rukn al-Dawla" ("Pillar of the State").