Shafii jurist who wrote the most significant classical theoretical explanation of public law in relation to political theory, Al-ahkam al-sultaniyyah (Ordinances of government). Lived and wrote during the period of political transition from Shii Buwayhids to Sunni Seljuks, which brought into question the type of leadership appropriate for Muslim communities. Emphasized the authority of the caliph over that of the sultan in order to strengthen the caliph's hand against military commanders who held the power behind the throne. Conceded the possibility of having more than one executive organ of political power, but insisted on the unity of ummah and on the symbolic unity of the office of caliph. Distinguished between religious (millah) and sociopolitical (ummah) forms of human association.