Final answer:
The claim that Constantine summoned and supervised the Council of Nicaea in 325 is true. He convened the council to settle the Arian controversy, leading to the establishment of the Nicene Creed, which stated that Jesus Christ was 'consubstantial' with God.
Step-by-step explanation:
The statement that Emperor Constantine summoned and supervised the Council of Nicaea in 325 is true. This first ecumenical council was convened primarily to address the Arian controversy regarding the divine nature of Jesus Christ. Constantine played a significant role in the council, seeking to unify the church and assert his imperial authority over religious matters. The bishops at the council ultimately rejected Arianism, affirming that Jesus Christ was "begotten, not made" and was consubstantial with God, leading to the adoption of the Nicene Creed.
While Constantine's involvement was significant, it is noteworthy that the debates and decisions were primarily carried out by the assembled bishops. Subsequent councils, such as the Council of Nicaea II, would continue to address theological disputes and the relationship between the church and imperial authority. Constantine's convening of the Council of Nicaea marked a pivotal moment in the Christian Church, establishing imperial influence in religious affairs and setting a doctrinal standard with the Nicene Creed.