Original sentence: Abu Bakr's immediate task was to avenge a recent defeat by Byzantine (or Eastern Roman Empire) forces, although he first had to put down a rebellion by Arab tribes in an episode known as the Ridda wars, or "Wars of Apostasy".During this time expansion continued, by both military warfare and by peaceful proselytism, as the monolithic Arab empire gave way to a more homogenized Muslim world.During this time, the decadence of the Umayyads inspired the formation of a movement of ascetics led by devout Muslims such as Hasan al-Basri.Muhammad began preaching Islam at Mecca before migrating to Medina, from where he united the tribes of Arabia into a singular Arab Muslim religious polity under his leadership.The first stage in the conquest of India began around the year 1000, at the same time that both Islam and Muslim trade networks were extending into sub-Saharan West Africa, Inner Asia, Volga Bulgaria and the Malay archipelago.The major hadith collections were compiled and the four modern Sunni Madh'habs were established even in the face of antagonistic regimes.This choice was disputed by some of Muhammad's companions, who held that Ali ibn Abi Talib, his cousin and son-in-law, had been designated his successor
Edited sentence: (This choice was disputed by some of Muhammad's companions, who held that Ali ibn Abi Talib, his cousin and son-in-law, was in fact his designated successor.) Abu Bakr's immediate task was to avenge a recent defeat by Byzantine (or Eastern Roman Empire) forces, although he first had to put down a rebellion by Arab tribes in an episode known as the Ridda wars, or "Wars of Apostasy".During this time expansion continued—sometimes by military warfare and sometimes by peaceful proselytism.During this time, the decadence of the Umayyads inspired the formation of a movement of ascetics led by a devout Muslim named Hasan al-Basri.Islam began in Arabia in the 7th century under the leadership of Muhammad, who united the tribes of Arabia under his rule.The first stage in the conquest of India began around the year 1000, at the same time that Islam was established in sub-Saharan West Africa