The Latin word basilica (derived from Greek, βασιλική στοά, Royal Stoa, the tribunal chamber of a king), was originally used to describe a Roman public building, usually located in the forum of a Roman town. Public basilicas began to appear in Hellenistic cities in the 2nd century BCE.
The term was also applied to buildings used for religious purposes. The remains of a large subterranean Neopythagorean basilica dating from the 1st century AD were found near the Porta Maggiore in Rome in 1915. The stuccoes on the interior vaulting have survived, though their exact interpretation remains a matter for debate. The ground-plan of Christian basilicas in the 4th century was similar to that of this Neopythagorean basilica, which had three naves and an apse.
After the Roman Empire became officially Christian with the Edict of Thessalonica in 380, the term, by extension, came to refer specifically to a large and important church that has been given special ceremonial rites by the Pope. Thus the word retains two senses today, one architectural and the other ecclesiastical.
