The unification and expansion of the Arabs under the first four caliphs (632–661)
The first four caliphs, successors of Muḥammad (d. 632):
ʿAbdallāh Abū Bakr (632–634)
ʿUmar ibn al-Ḫaṭṭāb (634–644)
ʿUtmān ibn ʿAffān (644–656)
ʿAlī ibn Abī Ṭālib (656–661)
Muḥammad met such resistance to his doctrine in Makka/Mecca, the town of his birth, that he emigrated with his followers in 622, after long preparations, to the oasis city of Yaṭrīb, subsequently al-Madīna (‘City [of the Prophet]’), where he had engendered great hopes as a mediator in the conflicts between various Arab tribes of the region.