 In the assessment of his biographer Chase F. Robinson, "Mu'awiya may have introduced the principle of dynastic succession into the ruling tradition of early Islam, but Abd al-Malik made it work".Abd al-Malik's concentration of power into the hands of his family was unprecedented; at one point, his brothers or sons held nearly all governorships of the provinces and Syria's districts.Likewise, his court in Damascus was filled with far more Umayyads than under his Sufyanid predecessors, a result of the clan's exile to the city from Medina in 683.