This paper examines whether Columbanus’ understanding of the Christian message of salvation was influenced by the writings of Pelagius. It looks at what Columbanus knew about the controversy surrounding Pelagius, and how Columbanus’ dispute with bishops in Gaul related to the controversy over the relationship between prevenient grace and effective human free will. Evidence from his letters suggests that Columbanus modified his conception of Christian doctrine in response to criticism he experienced in Gaul. This paper will examine these questions to ask how far the teachings of Pelagius were part of Columbanus’ sense of his Christian identity.