Canon 8, Council of Nice:
Concerning those who call themselves Cathari, if they come over to the Catholic and Apostolic Church, the great and holy Synod decrees that they who are ordained shall continue as they are in the clergy.
NOTE: The Cathari were the Novatians whose baptism was the cause of the debate between Pope St. Stephen and St. Cyprian. This canon, by accepting the ordinations of the Novatians as valid, indicated that their baptisms were also considered valid by the Church.
Canon 19, Council of Nice I:
Concerning the Paulianists…if any of them who in past time have been numbered among their clergy should be found blameless and without reproach. let them be rebaptized and ordained by the Bishop of the Catholic Church.
So why were the baptisms/ordinations of the Novatians/Cathari accepted, while those of the Paulianists were rejected? Exactly as brother Aramis stated. The Paulianists, followers of Paul of Samosota, were anti-Trinitarians and did not baptize “In the name of the Father, and of the Son and of the Holy Spirit.” On the other hand, the Novatians did.
Canon 7, Council of Constantinople I:
Those who from heresy turn to orthodoxy…Arians, Macedonians, Sabbatians, Novatians…Quarto-decimans, Apollinarians, we receive upon their giving a written renunciation of their errors and anathematize every heresy which is not in accordance with the Holy, Catholic, and Apostolic Church of God. Thereupon, they are first sealed or anointed with the holy oil…But Eunomians…Montanists…Sabellians…and all other heresies…we receive as heathen.
Why were the baptisms of the first set of heretics accepted, while the baptisms of the second set rejected as invalid?
According to Socrates of Constantinople, Eunomians changed the baptismal formula as baptism “In the name of the Creator.” It’s relevant that Eunomians were a sect of Arians, but the baptism of Arians was accepted. St. Cyprian informs us that Montanists baptized in the Name of Christ only. Tertullian tells us that the Sabellians baptized in the name of a uni-personal God, not the Father, Son and Holy Spirit.
My favorite early patristic quote on the matter is from Pope St. Dionysius of Alexandria in the 3rd century: “Those baptized in the name of three persons…though baptized by heretics…shall not be rebaptized. But those converted from other heresies shall be perfected by the baptism of the Holy Church.”
Blessings,
Marduk