Islam is an Abrahamic, monotheistic religion centered on the Quran and the teachings of Muhammad, the religions founder. Adherents of Islam, called Muslims, number approximately 1.9 billion globally and are the worlds second-largest religious population after Christians. The religion of Islam originated in Mecca about 610 CE, and Muslims believe this is when Muhammad began receiving revelation. By the time of his death, most of the Arabian Peninsula had converted to Islam. Islam means to achieve peace – peace with God, peace within oneself, and peace with the creations of God – through wholly submitting oneself to God and accepting His guidance. The term Islam derives from the Arabic root word "sa-la-ma," which means peace. So, the complete meaning of "Islam" is attaining a state of peace by submitting oneself to the Will of Almighty God, and by definition, one who does this is called a "Muslim." Islam is not a new religion, but rather a reestablishment of the "primordial" religion of humankind, centered around belief in the One God and commitment to His commandments. Muslims believe in One, Unique, and Incomparable God, the Day of Judgment, and individual accountability for actions. The Quran is the record of the exact words revealed by God through the Angel Gabriel to the Prophet Muhammad.