Basilica (Gr. from , king), a term first applied in Athens to buildings in which public business was transacted, and afterward in Rome to stately edifices of an oblong shape, with four corners, adorned with Corinthian columns, generally used for the administration of justice, and for other public purposes. The first basilica at Rome was built by Cato the Elder, and was called Porcia. The basilica Julia, built by Vitruvius at Fanum for Julius Caesar, was supported by 100 marble pillars, embellished with gold and precious stones, and contained 13 judgment seats for the praetors. There were about 20 basilicas in Rome, and one in every provincial town. The only one of which considerable remains still exist is that of Trajan. Among the most celebrated basilicas were those at Palestrina, Pompeii, and Paestum. Many of them became churches, some of which in the 4th and 5th centuries were called basilicas; and the term was also given to the tomb of Edward the Confessor and other mediaeval church-like sepulchral monuments.
There are several churches in Rome called basilicas, but the name is chiefly applied in modern times to the five patriarchal churches of St. Peter, St. John Lateran, Santa Maria Maggiore, St. Paul, and St. Lorenzo, the last two being without the walls. Of the smaller basilicas the most important are those of Santa Croce, St. Sebastian, St. Agnes, and San Pietro in Vincoli. - See Bunsen, Die christlichen Basiliken Boms (Munich, 1843), and Hubsch, Der altchristliche Kirchenbau (Carlsruhe, 18G2).