According to history-World.org"The Spread Of Islam, The Islamic state expanded very rapidly after the death of Muhammad through remarkable successes both at converting unbelievers to Islam ... successfully established the new faith through conversion and conquest of ... consolidating their power throughout the Arabian peninsula and began to launch" all over the world by the book Quran which is a holy book from Allah to straight people to the right path, and Islam growth very fast because the followers are really strict to their tradition from the prophet Muhammad Peace Upon Him.
