over the next fifty years , under the umayyad caliphs , the arabs would launch Military_operation repeated raids Attack into unk asia minor , twice besiege Besieging the byzantine capital of constantinople , and conquer Conquering the byzantine exarchate of africa .

over the next fifty years , under the umayyad caliphs , the arabs would launch Military_operation repeated raids Attack into unk asia minor , twice besiege Besieging the byzantine capital of constantinople , and conquer Conquering the byzantine exarchate of africa .