The Prophet Mohammed was born in the northern Arabian trading
city of Mecca between 570 and 580 AD. When he was forty years old, he heard the angel Gabriel speaking
to him and telling him to start a new religion: Islam. After a slow start, Mohammed made a lot
of converts to his new religion, and they began attacking other Arabian tribes to convert
them to Islam. After they had done that, they attacked first the Romans and then the Sassanids to convert them.