Muhammad had become the head of a collection of tribal groups that were not bound together by blood but by a shared ideology, an astonishing innovation in Arabian society. Nobody was forced to convert to the religion of the Quran, but Muslims, pagans and Jews all belonged to one ummah, could not attack one another, and vowed to give each other protection. News of this extraordinary new 'supertribe' spread, and though at the outset nobody thought that it had a chance of survival, it proved to be an inspiration that would bring peace to Arabia before the death of the Prophet in 632, just ten years after the hijrah.