This position was in contrast to the Novatianists, who held that those who failed to maintain their confession of faith under persecution would not be received again into communion with the church.

Cornelius held a synod that confirmed his election and excommunicated Novatian, but the controversy regarding lapsed members continued for years.

Emperor Decius, who ruled from 249 to 251, persecuted Christians in the Roman Empire rather sporadically and locally, but starting in January of the year 250, he ordered all citizens to perform a religious sacrifice in the presence of commissioners, or else face death.

One side, led by Novatian, a priest in the diocese of Rome, said those who had stopped practising Christianity during the persecution could not be accepted back into the church, even if they repented.

[4] The opposing side, including Cornelius and Cyprian of Carthage, said the lapsi could be restored to communion through repentance, demonstrated by a period of penance.

[5] Cornelius's next action was to convene a synod of 60 bishops to acknowledge him as the rightful pope and the council excommunicated Novatian as well as all Novatianists.

The letters he sent while in exile are all written in the colloquial Latin of the period instead of the classical style used by the educated such as Cyprian, a theologian as well as a bishop, and Novatian, who was also a philosopher.

The daughter of a local townsman fell in love with the artist, but her father forbade the marriage, remarking that he would only consent if the pope did as well.

Cornelius, along with Quirinus of Neuss, Hubertus and Anthony the Great, was venerated as one of the Four Holy Marshals in the Rhineland during the late Middle Ages.