Islam, one of the world’s largest religions, originated with the teachings of the prophet Muhammad (c. 570–632) during the early 600s. Muhammad was born in Mecca (in present-day Saudi Arabia) and was orphaned at the age of six. He was raised by relatives, who trained him as a merchant. When he was 25 years old he married a wealthy widow, Khadijah, who bore him several children. In about 610, Muhammad began having visions in which he was called upon by God (Allah). More than 600 of these visions were written down, becoming the sacred text known as the Koran (or Qur’an). By 613 Muhammad had attracted followers with his messages of one God, Allah’s power, the duty of worship and generosity, and the doctrine of the last judgment. Followers of this new religion became known as Muslims, an Arabic word meaning “those who submit” (to Allah); and the religion itself became known as Islam (meaning submission).

Today, there are Muslims in every part of the world, but the largest Muslim communities are in the Middle East, North Africa, Indonesia, Bangladesh, Pakistan, India, and central Asia. Additionally, most of the people of Turkey and Albania are Muslim. It is the world’s second-largest religion (after christianity).