The Ismaili branch of Shia Islam split from the main Shia tradition over the succession to Jafar al-Sadiq (the 6th Imam, died 765 AD). The majority of Shia accepted Musa al-Kazim as the 7th Imam (leading to the Twelver tradition). The Ismailis followed Ismail ibn Jafar, Jafar’s elder son who had died before his father, insisting the imamate had already been designated to Ismail and then to his son Muhammad ibn Ismail. The Ismaili tradition developed a sophisticated esoteric (batin) theology that saw outer religious observances as pointing to inner spiritual meanings — influenced by Neoplatonism and Gnostic thought. The Fatimid Caliphate (909–1171 AD) in North Africa and Egypt was an Ismaili state that built Cairo and the al-Azhar mosque/university. The Ismailis split again in 1094 AD into Nizari and Mustali branches.