Architectural terms: Basilica

In the Roman Catholic church basilica {buh-sil'-i-kuh} is an honorary name given to certain churches. The original and still the most important basilicas are the four principle churches of Rome: Saint Peter's Basilica, San Giovanni in Laterano, Santa Maria Maggiore, and San Paolo Fuori le Mura.

The term basilica also refers to a particular architectural form. In Roman architecture, where it originated, a basilica was a large, oblong building used particularly as a court of law and a place of public assembly. In Early Christian and Merovingian times, the function of the basilica became exclusively religious, and the plan was often varied by transepts, or side wings, frequently with domes over the resultant crossing.

Basilica plan

The Basilica Ulpia (98-112) in Trajan's Forum, Rome, was designed by Apollodorus of Damascus. The plan reveals a typical basilican structure with a wide central nave, double side aisles, and raised tribunals in semicircular apses with sacrificial altars at either end.


Although the name is derived from the Greek basilike (meaning "royal"), the Basilica Porcia, the earliest known, was built (184 B.C.) by Cato the Elder in republican Rome. It was so useful that others were built throughout the Roman world, usually adjoining the forum or agora of a town. The earliest preserved basilica (2d century B.C.) has been found in Pompeii. Its main entrances were at one end of the rectangle, but it also had a doorway in the center of each long wall. An inner, rectangular colonnade supported the roof, but the center may have been open to the sky (in later basilicas these colonnades were reorganized to form aisles). At the end opposite the main doors was a rectangular tribunal, two stories high, with a subsidiary room on either side. Although the ends of basilicas could be rectangular or semicircular (forming an apse) and could include the side rooms or not, the scheme remained basically constant in Roman practice. Vitruvius (active 46-30 B.C.) gave detailed directions for building such basilicas in his treatise on Roman architecture.

The form of the basilica lent itself to public assembly for religious rites. A rare pagan religious basilica dating from the reign (A.D. 14-37) of Tiberius was discovered in Rome near Porta Maggiore. The form was widely used, however, for synagogues in Palestine and at Sardis, Turkey, from at least the 2d century A.D.

When early Christian congregations grew too large to meet in titulae (houses), they adopted the basilican form for their own use. Constantine's 4th-century donations of monumental basilicas at all the major holy sites throughout the Roman world strengthened the popularity of the form. Although variations were many, the hall remained long and rectangular. If it was extremely wide, it might be divided by colonnades or arches into three or more aisles, the center aisle, or nave, remaining the most important. In many basilicas the ceiling of the nave was raised by placing a wall pierced with windows (the clerestory) above the side colonnades. The hall might be beam-roofed, vaulted, or domed. An altar took the place of the Roman tribunal. The rooms on either side, when they were retained, could be used as the prothesis and diakonikon (rooms in which the sacraments, books, and vestments were stored) in the Byzantine church. In Western churches they became side altars, chapels, and sacristies as Romanesque and Gothic architecture developed.

The basilica thus served as the basic plan for the majority of churches in the past, and it continues to be the most popular form for houses of worship today.

John Stephens Crawford, Associate Professor of Art History, University of Delaware, Newark.
Source: 2001 Grolier Multimedia Encyclopedia, ©2000 Grolier Interactive Inc. — All Rights Reserved.
Bibliography: Axel Boethius and J. B. Ward-Perkins, Etruscan and Roman Architecture (1969); Richard Krautheimer, Early Christian and Byzantine Architecture (1965; repr. 1975); Donald Robertson, A Handbook of Greek and Roman Architecture, 2d ed. (1969); Vitruvius, The Ten Books on Architecture (1960).
Relevant publications: Catherie Guigon, Les Mystères du Sacré-Coeur (1998 - in French). J. Benoist, Sacré-Coeur Montmartre, Voeu National (1997 - in French). Pierre Boucaud, Vézelay: Un guide raconte la basilique (1998 - in French). Robin S. Oggins, Cathedrals (1996).
Image: Basilica lay-out, from 2001 Grolier Multimedia Encyclopedia, ©2000 Grolier Interactive Inc. — All Rights Reserved.