 At the very beginning of his reign , he deemed it proper to promulgate by law the Church 's belief in the Trinity and the Incarnation ; and to threaten all heretics with the appropriate penalties ; whereas he subsequently declared that he intended to deprive all disturbers of orthodoxy of the opportunity for such offense by due process of law . He made the Nicaeno @-@ Constantinopolitan creed the sole symbol of the Church , and accorded legal force to the canons of the four ecumenical councils . The bishops in attendance at the Second Council of Constantinople in 553 recognized that nothing could be done in the Church contrary to the emperor 's will and command ; while , on his side , the emperor , in the case of the Patriarch Anthimus , reinforced the ban of the Church with temporal proscription . Justinian protected the purity of the church by suppressing heretics . He neglected no opportunity for securing the rights of the Church and clergy , for protecting and extending monasticism . He granted the monks the right to inherit property from private citizens and the right to receive solemnia or annual gifts from the Imperial treasury or from the taxes of certain provinces and he prohibited lay confiscation of monastic estates . 
