Islam began in the 7th century AD in Mecca under the prophet Muhammad. It is a monotheistic religion that believes in one God, Allah. When Muhammad began preaching his message of monotheism, he gained many followers but also faced opposition from Meccans who worshipped many gods. Muhammad and his followers then migrated to Medina and later conquered Mecca, establishing it as the holiest city in Islam. The religion expanded rapidly under the rule of caliphs and through military conquest, establishing a vast empire across North Africa, the Middle East and parts of Europe. Islam split into the two main sects of Sunni and Shia after disagreements over leadership succession following Muhammad's death. Today it