Muslims
Muhammad united Arabia into a single Muslim polity, with the Qur'an forming the basis of Islamic religious belief. Muslim conquests following Muhammad's death led to the creation of the Arab caliphates, occupying a vast geographical area. The Islamic conquests culminated in the Arab Empire being established across three continents (Asia, Africa, and Europe). Today, there are about 1.57 billion Muslims in the world, which is about 1 person in every 4 people. The Muslim population continues to grow.