In the year 250, when the Roman presbyter Novatian wrote his book De Trinitate, the doctrine of Hippolytus, once discredited as ditheism, had already become official there.
Bishop Fabian suffered martyrdom in January 250, and, when Cornelius was elected his successor in March or April 251, Novatian objected on account of his known laxity on the above-mentioned point of discipline, and allowed himself to be consecrated bishop by the minority who shared his views.
He is greatly indebted to oral tradition and to the testimony of eye-witnesses, especially of members of the Novatian community in Constantinople; some things also he has set down from personal knowledge.
The Novatian controversy can be advantageously studied in the Epistles of Cyprian.
Hippolytus and Novatian repeat the protest less vehemently; Donatism shows it blended with later hierarchical ideas.
He was highly esteemed by Cyprian, bishop of Carthage; Novatian refers to his nobilissimae memoriae, and he corresponded with Origen.
The practice gave rise to complicated problems of ecclesiastical discipline, which are reflected in the correspondence of Cyprian and especially in the Novatian controversy.
In May 251 a synod, assembled under the presidency of Cyprian to consider the treatment of the lapsi (those who had fallen away from the faith during persecution), excommunicated Felicissimus and five other Novatian bishops (Rigorists), and declared that the lapsi should be dealt with, not with indiscriminate severity, but according to the degree of individual guilt.