High Quality Content by WIKIPEDIA articles! The Byzantine–Arab Wars were a series of wars between the Arab Caliphates and the East Roman or Byzantine Empire between the 7th and 12th centuries AD. These started during the initial Muslim conquests under the expansionist Rashidun and Umayyad caliphs and continued in the form of an enduring border tussle until the beginning of the Crusades. As a result, Arab controlled territory expanded considerably.