Soon after his return to Medina in the year 632 CE (AH 10), the Prophet received the last revelation of the Qur’an and, shortly thereafter, died. His role as leader of the Islamic state was taken over by Abu Bakr (632–4 CE), followed by ‘Umar (634–44) and ‘Uthman (644–56), who oversaw the phenomenal spread of Islam beyond Arabia. They were followed by ‘Ali (656–61). These four leaders are called the Rightly Guided Caliphs.
