schism · 251 · Rome
The Decian persecution had produced thousands of lapsed — some who sacrificed, some who bought certificates saying they had — and when it lifted they wanted back in. Novatian, the ablest theologian the Roman church had produced and the author of the first substantial Latin treatise on the Trinity, held that it had no power to readmit them: God might forgive apostasy, but the church could not presume to. He lost the election to Cornelius and was then consecrated bishop against him. Cornelius' account, which Eusebius preserves and which is not disinterested, says three bishops were fetched from the country, entertained, and ordained him while drunk. Cyprian, who had just fought the opposite battle at Carthage against rigorists in his own clergy, backed Cornelius, and the African and Eastern churches followed. The Novatianists called themselves the Pure and lasted as a separate church into the sixth century, keeping their own bishops and their own buildings; the councils that dealt with them argued mainly about whether their baptism counted, which is the same question Cyprian and Stephen would quarrel over five years later.
To keep the church from readmitting Christians who had sacrificed to save their lives.
A rival Roman church that outlived its founder by three hundred years, and the question of whether the church can forgive apostasy, settled against him.