Pelagians were followers of the teachings of the teacher Pelagius (c. 354—420/440) which was condemned as heresy by the Church hierarchy.
Pelagians did not believe in original sin as defined by many of their opponents, and some did not believe that the Church itself was necessary to salvation, although it was a great help to salvation.
Pelagius, himself, was known as a Briton, but had “lived long” in Rome and was generally recognized as a very virtuous man. St. Jerome stated that Pelagius was “stuffed with Scottish porridge”. Pelagus himself in some letter fragments dissented from some of the viewpoints put forth by his followers.
Pelagianism was especially opposed by St. Augustine of Hippo ((November 13, 354 – August 28, 430).
The Life of St. Germanus tells how Germanus made two journeys to Britain to oppose Pelagiansim around 429 and later. This source, in both cases, claims that Germanus’ preaching was successful, but gives few details.