 Nicaea I canon 5 "implied that" provincial synods "had an acknowledged authority to" judge the acts of individual bishops of their province.Provincial synods' authority "was becoming well established in the East" prior to the council of Serdica.In 431, the Synod of Antioch canons 14 and 15 "were designed both to augment the authority of the provincial synod as a trial court and to ensure the integrity of its operation."