On the 24th of Dhu-al-Qa'da in the Islamic year 309, the 26th of March in the Christian year 922, a man was executed for religious crimes in the city of Baghdad in Iraq. Baghdad at that time had been the seat of Muhammad's political successors, the caliphs, since the middle of the eighth century and was the capital of much of die Islamic community. As a political institution, the caliphate was sunni, modeled on the surma, or path, of Muhammad— at least in theory.