The life of the Prophet Muhammad began in Mecca around 570 CE. He belonged to the Quraysh tribe and worked as a merchant. At the age of 25, he married Khadijah, a wealthy widow. At 40, he began receiving revelations from Allah through the angel Gabriel, which later became the Qur'an. As he preached monotheism, he faced opposition from the Quraysh leaders. In 622 CE, he and his followers migrated to Medina, an event known as the Hijra. Over the next decade, he united the tribes of Arabia and established Islam as a major religion before his death in 632 CE.