This paper presents a short description of the emergence of Christianity and persecution of Christians, and shows the political situation in the Roman Empire until the arrival to power of Constantine the Great. In order to maintain the hard-won peace, both in the Empire and the Church, the First Ecumenical Council of Nicaea was held in 325, which condemned the heretical teaching priest Arius, and Christianity as a state religion. At the Council of Nicea and afterwards, bishops as representatives of the local church, agreed with the decision of Parliament, and the emperor to accept the term „homoousios“. This would not be questioned that the imperial will was the main factor in this acceptance. In order to maintain peace and order in the Church banished the main opponents of this confession and thought that their exile this case is closed. However, the car did not expect those same exiled bishops, who were at the forefront of the most respected local churches, submitted a false confession of faith just to regain his position. These followers of the Arian heresy in all ways trying to various charges before the king blacken great champions of Orthodoxy, while his supporters justified and suggest that the emperor should be returned from exile. Car as the highest instance of how the state and the Church, Parliament convened again slightly in order to solve the burning issues related to peace in the Church. In conclusion, it points out that after I Ecumenical Council Arians were closer to the emperor, as confirmed by his baptism before the death of the bishop Eusebius of Nicomedia.