His parents were Catholics, but early in life he was taken against his will by the Donatists, baptised and eventually made their bishop around 395 to 400.
[4] About 398 to 400, Augustine invited leaders of the Donatist sect in Cirta to discuss the questions at issue between them and the Catholic Church.
Petilianus later sent a letter to Augustine, proposing a separation from the Catholic Church, due to what he perceived as "pollution of the souls" through the repetition of baptism.
As Bishop of Cirta he had a leading role at the Council of Carthage (411), being one of the seven managers on the Donatist side.
He was furthermore accused on the third day of the Council of losing his temper and insulting Augustine personally.