Ridda wars
One writer states that Omar was a political genius and, as an architect of the Islamic Empire, rates him as the 52nd most influential figure in history. Omar was one of Muhammad's chief advisers. After Muhammad's passing, it was Omar who reconciled the Medinan Muslims to accept Abu Bakr, a Meccan, as the caliph. During Abu Bakr's era, he actively participated as his secretary and main adviser. After succeeding Abu Bakr as caliph, Omar won over the hearts of Bedouin tribes by emancipating all their prisoners and slaves taken during the Ridda wars.