This is an English translation of the central religious text of Islam, which Muslims believe to be a revelation from God (Allah). It is widely regarded as the finest work in classical Arabic literature. The Quran is divided into chapters (surah in Arabic), which are then divided into verses (ayah). Muslims believe that the Quran was verbally revealed by God to Muhammad through the angel 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 Quran 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. The word "Quran" occurs some 70 times in the text of the Quran, although different names and words are also said to be references to the Quran.