 The collapse of Umayyad authority precipitated by Mu'awiya I's death made it apparent to Abd al-Malik that the decentralized Sufyanid system was unsustainable.Moreover, despite the defeat of his Muslim rivals, his dynasty remained domestically and externally insecure, prompting a need to legitimize its existence, according to Blankinship.Abd al-Malik's solution to the fractious tribalism which defined his predecessors' caliphate was to centralize power.