The Basilica of Maxentius and Constantine (Basilica di Massenzio) is the largest ancient building in the Roman Forum. Construction began on the northern side of the forum under the emperor Maxentius in 308, and was completed in 312 by Constantine I after his defeat of Maxentius at the Battle of the Milvian Bridge. The building rose close to the Temple of Peace, at that time probably neglected, and the Temple of Venus and Rome, whose reconstruction was part of Maxentius' interventions.
The building consisted of a central nave covered by three groin vaults suspended 39 meters above the floor on four large piers, ending in an apse at the western end containing a colossal statue of Constantine (remnants of which are now in a courtyard of the Palazzo dei Conservatori of the Musei Capitolini).
The south and central sections were probably destroyed by the earthquake of 847. In 1349 the vault of the nave collapsed in another earthquake. The only one of the eight 20-meter-high columns, which survived the earthquake was brought by Pope Paul V to Piazza Santa Maria Maggiore in 1614. All that remains of the basilica today is the north aisle with its three concrete barrel vaults. The ceilings of the barrel vaults show advanced weight-saving structural skill with octagonal ceiling coffers.
References:The Cathedral of Saint Mary Major, often called Lisbon Cathedral or simply the Sé, is a Roman Catholic cathedral located in Lisbon, Portugal. The oldest church in the city, it is the seat of the Patriarchate of Lisbon. The cathedral has survived many earthquakes and has been modified, renovated and restored several times. It is nowadays a mix of different architectural styles.
The site where it stands was the principal mosque of Lisbon when it was an Arab settlement. The construction of the cathedral started around 1150, three years after the city was conquered from the Moors during the Second Crusade. Shortly after the victory the English knight Gilbert of Hastings was named bishop of the city of Lisbon.
One good reason to visit the Cathedral is to visit its charming cloisters located in the back. There are several tombs in the cathedral, the most notable of which is the beautifully sculpted tomb of Lopo Fernandes Pacheco and his wife.