610 A.D. The prophet Muhammad is visited by the Angel Gabriel.
The angel ordered Muhammad to recite the words of Allah. And he continued to recieve these relavations for the rest of his life.
In 613 A.D. he started sharing the messages sent by Allah, and the religions influence expanded.
In 622 A.D. he and his followers travelled to Medina, from Mecca this was known as the Hijra
Eventually the prophet died. But his life mission of spreading Islam was complete.
After that a ruler (usually related to the current one) would be chosen as the new Caliph e.g. Pope. These leaders would eventually become the Ottaman Empire. This ruling system lasted many more centuries.