Hijra

Muhammad moved from Mecca to Medina. The Islamic calendar counts its years from this event.

In the late 6th century Mecca prospered as a centre of the caravan trade, which had shifted to Arabia as wars between Byzantium and Sasanian Persia blocked older routes. Around 610 Muhammad began preaching revelations from the one God, Allah, calling on people to abandon idols and accept equality before God, but he was persecuted by Meccan notables who profited from pilgrimage to the Kaaba.

In 622 Muhammad and his followers moved to Yathrib at the invitation of its people, and the town came to be called Medina, "the city of the Prophet". There he led the community of believers, the umma, as religious, political and military leader. After years of fighting he entered Mecca in 630 and cleared the Kaaba of idols, and by his death in 632 most of Arabia had been united under Islam.

The second caliph, Umar, made the year of the Hijra the first year of the Islamic calendar, since it marked the moment a persecuted group became a polity. Under the Rashidun caliphs Islam expanded rapidly, destroying the Sasanian Empire and taking Syria and Egypt from Byzantium. Muslim merchants would later sail as far as Tang China and Unified Silla.