Colga served as abbot of the monastic school of Clonmacnoise, Ireland, where it is believed he had formerly been a student himself. He made the writings of Saint Paul the particular object of his studies, taking this apostle as his special patron. There is a tradition that Saint Paul appeared to Colga in several visions to instruct him, and even to assist him in winning a theological debate. Colga is the author of an eighth-century Irish prayer addressed to Christ, in which the ranks of apostles, evangelists, saints, angels, and Old Testament patriarchs and prophets are invoked to plead for mercy and forgiveness from God. The contents of the text demonstrate a theological conformity and communion with the Church of Rome that refutes the false assertion made by some that the early Irish Church was theologically "independent" of Rome. The prayer also contains a moving plea beseeching Christ to convert all who are hostile to the Church: "May God enkindle meekness, and charity, and love, and mercy, and affection in their hearts, and in their thoughts, and in their souls, and in their minds."
