Constantine's main contribution to imperial Christian art was in the form of grand monumental architecture. In Rome, where he spent only a few months of his life, he had constructed the first Vatican basilica over the tomb of St. Peter, and the church of what is now known as St. John Lateran, as well as the largest Roman triumphal arch ever built. In the rest of the empire, he built imposing basilicas as far apart as the Church of the Holy Apostles in Constantinople and that of Trier in Germany.