Rome: Basilica of Maxentius, in the Roman forum. Its construction began in 308 under the emperor Maxentius and was completed by Constantine I in 312, after the defeat of Maxentius at the battle of the Milvian Bridge. The building consisted of a central nave covered by three groin vaults ending in an apse at the western end containing a colossal statue of Constantine. The weight of the groin vaults was supported by flanking aisles. All that remains of the basilica today is the north aisle with its three concrete barrel vaults.