From its inception, Islamic government had to learn from the great imperial experiments of its time: the Sassanids in Persia and the Byzantines in Anatolia, which combined empire and religion. The Prophet Muhammed, consciously or not, adopted this model in his ten years of rule in Medina (AD 622-32), for without his experience as a preacher in Mecca he would not have been invited to Medina, and without his ruling experience in Medina, it is doubtful whether his prophetic experience in Mecca would have served any practical purpose and accorded him his fame as the founder of Islam. The mold of government developed by Muhammed through his Medina experience while he was setting the first example of rule in the first Muslim polis consisted of five functions: prophecy, legislation, administration, judiciary, and military.