Before revision: Medieval era The Islamic Caliphate's defeats of the Byzantine and Persian empires led to West Asia and southern parts of Central Asia and western parts of South Asia under its control during its conquests of the 7th century; Islam also spread over centuries to the southern regions of India and Southeast Asia through maritime trade .
After revision: Medieval era The Islamic Caliphate's defeats of the Byzantine and Persian empires led to West Asia and southern parts of Central Asia and western parts of South Asia under its control during its conquests of the 7th century; Islam also spread over centuries to the southern regions of India and Southeast Asia through trade along the Maritime Silk Road .