One pagan idea that Constantine retained was his opinion of theology, particularly that which dealt with the origin of Christ. In a letter to Arius and Alexander, Constantine asked them to forget their theological differences. In Barnes' words, Constantine "urged Arius and Alexander to act like philosophers."59 According to Barnes, Constantine also believed that Christians can legitimately agree on certain points while accepting each other in the faith.60 What Constantine did see as important in ensuring the support of God, however, was the actual method of worship.61 This emphasis on ritual rather than theology in religion was an important characteristic of Roman paganism.
Other pagan ideas in which Constantine seems to have believed are the use of divination and magic, which Christians of the day were strongly against. In 321, Constantine outlawed the private use of haruspices (diviners) and magic, although he allowed for the use of haruspices in public ceremonies and spells that were used to heal the sick.62
59. Barnes, 213.
60. Ibid., 213.
61. See Stevenson, 284-285 ("The Edict of Milan") and Stevenson, 288-289 ("Constantine to Anulinus").
62. Alfoldi, 78.