Battle of Milvian Bridge; Constantine converts to Christianity
313
Edict of Milan grants official toleration of Christianity in the Roman Empire
315
Construction of the Arch of Constantine
324
Constantine commissions St. Peter's Basilica in Rome
325
Council of Nicea
326
Constantine the Great begins construction on Trier Cathedral on the site of his mother Helena's imperial palace. Four times larger than the present cathedral, it occupies the site of the present cathedral, the Leibfrauenkirche, Cathedral Square, the adjoi
