Muslims believe that the Koran was verbally revealed by God to the final Prophet Muhammad through the archangel Gabriel (Jibril), gradually over a period of approximately 23 years, beginning on 22 December 609 CE, when Muhammad was 40, and concluding in 632, the year of his death.
Muslims regard the Koran as the most important miracle of Muhammad, a proof of his prophethood, and the culmination of a series of divine messages that started with the messages revealed to Adam and ended with Muhammad.