Basilica of Maxentius and Constantine

Remains of the Basilica of Maxentius and Constantine. The building's northern aisle is all that remains.
Location	Regione VIII Forum Romanum
Built in	312 AD
Built by/for	Maxentius, Constantine I
Type of structure	Basilica
Related	List of ancient monuments in Rome
Basilica of Maxentius and Constantine

Coordinates: 41°53′30″N 12°29′18″E / 41.891775°N 12.488446°E / 41.891775; 12.488446

The Basilica of Maxentius and Constantine (Italian: Basilica di Massenzio), sometimes known as the Basilica Nova - meaning "new basilica" - or Basilica of Maxentius, is an ancient building in the Roman Forum, Rome, Italy. It was the largest building in the 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 lateral forces of the groin vaults were held by flanking aisles measuring 23 by 17 metres (75 x 56 feet). The aisles were spanned by three semi-circular barrel vaults perpendicular to the nave, and narrow arcades ran parallel to the nave beneath the barrel vaults. The nave itself measured 25 metres by 80 metres (83 x 265 feet) creating a 2000 square meter floor. Like the great imperial baths, the basilica made use of vast interior space with its emotional effect.