Definition
Islam is a monotheistic religion that emerged in the Arabian Peninsula in the early seventh century CE. Its followers, called Muslims, believe that the Prophet Muhammad received revelations from God, collected in the holy book known as the Quran.
The word "Islam" means submission — specifically, submission to the will of the one God, called Allah in Arabic. Islam regards itself as the final completion of the same monotheistic tradition that includes Judaism and Christianity, and it spread rapidly to become one of the world's major religions.
Why it matters
How it works
Islam organizes life around the relationship between the believer and God, expressed through regular ritual, ethical conduct, and community. The Quran, together with the recorded sayings and example of Muhammad, provides guidance that shaped law, family life, commerce, and governance in Muslim societies.
Because Islam made no firm separation between religious and political authority in its early centuries, the spread of the faith and the spread of Muslim states often advanced together. This fusion shaped the rise of the caliphate and the empires that followed.