Records from that time mention his letters. One such letter is an admonishment of the moral laxity in the Church at Corinth. Another is regarding who can touch the sacred cloths used in the Mass.
The issue of when to celebrate Easter was discussed again and Catholics were instructed to celebrate the day on a Sunday rather than on Passover which some Churches, particularly in Asia Minor, were doing. He is considered a Saint of the Catholic Church and his feast day is celebrated on April 22.