The word “basilica” is often associated with early Christian building projects, like the Old St. Peters Basilica (to differentiate from the St. Peter’s Basilica standing on the same grounds today, more below). However, the basilica originated far earlier in classical Athens.
The Archon basileus was a position of high social import in classical Athens — the title translates as “king magistrate”. While it’s debatable just how much power the Archon basileus actually had, theoretically their job was to make final judicial calls, a service they carried out from a public portico. Eventually, a portico (of sorts) dedicated to judicial purposes passed into Roman culture, known as a basilica from the Greek basileus.
The Roman basilicas had strict styles, including lengths and measurements, as outlined by Marcus Vitruvius Pollio in his De architectura. Pollio was a Roman architect and military engineer in the service of Emperor Caesar Augustus. He notes that a basilica must be a parallelogram with a width no more than half the length, but no less than a third. A middle space, or nave, supported by columns and lined by porticos or ambulatories on the long sides, ambulatories should be as wide as they are tall, and the nave should be as wide as three ambulatories. Above the first level of columns should be another set, shorter and slighter, to let light into the main space and create a tapering-off effect. The size of the basilica comes down to the columns, as they determine the height of the ambulatories and therefore the width of both the ambulatories and the main space.
Basilicas had a range of uses in Ancient Rome, often functioning as mixed marketplaces with judicial spaces or courts of law built off the ambulatories in dedicated apses. Other basilicas were built into the homes of nobles, functioning as partially public reception areas.
In the early Christian era, basilicas presented covered spaces fit for large gatherings with minimal invasion of pagan gods. Except for the occasional shrine, basilicas were largely non-secular in ancient Rome … an ironic opposition to the present-day concept. As Rome became a Christian-tolerant state under Emperor Constantine I, the basilica became integral to the Catholic Church. Constantine instigated the building of the Old St. Peter’s Basilica, over what had been the Circus of Nero and is today the Vatican City.
The Old St. Peter’s preserved the Roman style of a large nave and side ambulatories, with an apse at the west end of the nave and two side aisles off the nave forming a Latin cross shape, a peculiarity that separates the Christian basilicas from the earlier Roman ones. Christian basilicas are largely found in Rome, with a few early renditions in Greece and Ravenna, Italy, but the style would influence design for centuries.
The basilica remained a mainstay inspiration of western Christianity throughout the ages as cathedrals were built in reminiscence of earlier buildings and older buildings were remodeled or rebuilt (in the case of St. Peter’s) to maintain the same cross-shaped place of worship comprised of naves, aisles, and ambulatories. Eastern Christianity, however, sprung from the basilica to a new design … a subject for next week.