[1] In ancient Rome, a basilica was a rectangular building with a large central open space, and often a raised apse at the far end from the entrance.

Basilicas served a variety of functions, including a combination of a court-house, council chamber and meeting hall.

Under Constantine and his successors this type of building was chosen as the basis for the design of the larger places of Christian worship, presumably as the basilica form had fewer pagan associations than those of the designs of traditional Greco-Roman temples,[2] and allowed large congregations.

[1] The building consisted of a central nave covered by three groin vaults suspended 39 metres (128 ft) 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).

[citation needed] Like the great imperial baths, the basilica made use of vast interior space with its emotional effect.

The only one of the eight 20-metre (66 ft) high columns that survived the earthquake was brought by Pope Paul V to Piazza Santa Maria Maggiore in 1614.

On the outside wall of the basilica, facing onto the via dei Fori Imperiali, are contemporary maps showing the various stages of the rise of the Roman Empire which were added during the Fascist regime of Benito Mussolini.

At that time, it used the most advanced engineering techniques known including innovations taken from the Markets of Trajan and the Baths of Diocletian.