Islam was a civilization born out of a religion. It was founded by the Prophet Mohammad after he declares that Gabriel was sent to speak to give him the word of God while he was on his annual solitary meditation retreat to the mountains near Mecca. As he gained followers his safety was questioned and he left Mecca. Over time Islam grew and spread. After Mohammad's death  his teachings were written down to form the Qu'ran and factions rose up due to the difference in belief over who should take over the leadership. Theses differences led to the split of Islam into two branches, the Shi'ites and the Sunnis. Over time the ongoing wars within Islam and from invaders began to chip away at the empire, but not the faith. By the early 1500s  the Islamic Empire was, for the most part, obliterated and it's lands divided.