The Koran is the compilation of the teachings of Mohammed. It was first collated in 650 A.D. by Othman, the third caliph, in Medina. Mohammed taught his religion, Islam, so therefore the Koran is the holy book of Islam. ”Koran” means recitation, and the Koran teaches that it should be “… in slow, measured rhythmic tones.”Koran 73:4. Mainly, the Koran teaches monotheism, that Allah is the only god. It also teaches that Mohammed is Allah’s greatest and last prophet, and that the prophets, such as Abraham, Moses, and Jesus, had received words from Allah, but Christians distort the words. But a very controversial teaching of the Koran is that Jesus is not the Son of God, merely a prophet; this goes against a basic Christian teaching.
I think the Koran has affected the world very much and still does to this day, since 20-25% of the world is Muslim, and once was the quickest growing religion in the world.