After the Roman Empire became officially Christian, the term came by extension to refer 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.
In architecture, the Roman basilica was a large roofed hall erected for transacting business and disposing of legal matters. Such buildings usually contained interior colonnades that divided the space, giving aisles or arcaded spaces at one or both sides, with an apse at one end (or less often at each end), where the magistrates sat, often on a slightly raised dais. The central aisle tended to be wide and was higher than the flanking aisles, so that light could penetrate through the clerestory windows.
Probably the most splendid Roman basilica (see below) is the one constructed for traditional purposes during the reign of the pagan emperor Maxentius and finished by Constantine after 313. As early as the time of Augustus, a public basilica for transacting business had been part of any settlement that considered itself a city, used like the late medieval covered markethouses of northern Europe (where the meeting room, for lack of urban space, was set above the arcades).
In the early Imperial period, a basilica for large audiences also became a feature in the palaces. In the 3rd century AD, the governing elite appeared less easily in the forums. "They now tended to dominate their cities from opulent palaces and country villas, set a little apart from traditional centers of public life. Rather than retreats from public life, however, these residences were the forum made private." (Peter Brown, in Paul Veyne, 1987). Seated in the tribune of his basilica the great man would meet his dependent clientes early every morning.
A private basilica excavated at Bulla Regia (Tunisia), in the "House of the Hunt," dates from the first half of the 4th century. Its reception or audience hall is a long rectangular nave-like space, flanked by dependent rooms that mostly also open into one another, ending in a circular apse, with matching transept spaces. The "crossing" of the two axes was emphasized with clustered columns.
In the 4th century, Christians were prepared to build larger and more handsome edifices for worship than the furtive meeting places they had been using. Architectural formulas for temples were unsuitable, not simply for their pagan associations, but because pagan cult and sacrifices occurred outdoors under the open sky in the sight of the gods, with the temple, housing the cult figures and the treasury, as a backdrop. The usable model at hand, when Constantine wanted to memorialize his imperial piety, was the familiar conventional architecture of the basilicas . These had a center nave with one aisle at each side and an apse at one end: on this raised platform sat the bishop and priests. Constantine built a basilica of this type in his palace complex at Trier, later very easily adopted for use as a church. It is a long rectangle two stories high, with ranks of arch-headed windows one above the other, without aisles (no mercantile exchange in this imperial basilica) and at the far end, beyond a huge arch, the apse in which Constantine held state. Exchange the throne for an altar, as was done at Trier, and you had a church. Basilicas of this type were built not only in Western Europe but in Greece, Syria, Egypt, and Palestine. Good early examples of the architectural basilica are the Church of the Nativity at Bethlehem (6th century), the church of St Elias at Thessalonica (5th century), and the two great basilicas at Ravenna.
Thus a Christian symbolic theme was applied quite naturally to form borrowed from civil semi-public precedents. In the later 4th century other Christian basilicas were built in Rome: Santa Sabina, St John Lateran and St Paul's-outside-the-Walls (4th century), and later San Clemente (6th century).
A Christian basilica of the 4th or 5th century stood behind its entirely enclosed forecourt ringed with a colonnade or arcade, like the stoa or peristyle that was its ancestor or like the cloister that was its descendant. This forecourt was entered from outside through a range of buildings along the public street. This was the architectural groundplan of St Peter's Basilica in Rome, until first the forecourt, then all of it was swept away in the 15th century to make way for a great modern church on a new plan.
In most basilicas the central nave is taller than the aisles, forming a row of windows called a clerestory. Some basilicas in the Caucasus, particularly those of Georgia and Armenia, have a central nave only slightly higher than the two aisles and a single pitched roof covering all three. The result is a much darker interior. This plan is known as the "oriental basilica."
Famous existing examples of churches constructed in the ancient basilica style include:
Gradually in the early Middle Ages there emerged the massive Romanesque churches, which still retained the fundamental plan of the basilica.
The Early Christian purpose-built basilica was the cathedral basilica of the bishop, on the model of the semi-public secular basilicas, and its growth in size and importance signalled the gradual transfer of civic power into episcopal hands, underway in the fifth century. Basilicas in this sense are divided into classes, the major ("greater"), and the minor basilicas, i.e., three other patriarchal and several pontifical minor basilicas in Italy, and over 1,400 lesser basilicas on all continents.
As of March 26 2006, there were 1,476 basilicas, of which the majority are in Europe (526 in Italy alone, including all those of elevated status; 166 in France; 96 in Poland; 94 in Spain; 69 in Germany; 27 in Austria; 23 in Belgium; 13 in the Czech Republic; 12 in Hungary; 11 in the Netherlands; and less than ten in many other countries), many in the Americas (58 in the U.S.; 47 in Brazil; 41 in Argentina; 27 in Mexico; 25 in Colombia; 21 in Canada; 13 in Venezuela; 12 in Peru; etc), and fewer in Asia (14 in India; 12 in the Philippines; nine in Israel; and some other countries one or two), Africa (several countries one or two) and Australasia (Australia 5 and Guam one).
The privileges attached to the status of basilica, which is conferred by Papal Brief, include a certain precedence before other churches, the right of the conopaeum (a baldachin resembling an umbrella; also called umbraculum, ombrellino, papilio, sinicchio, etc.) and the bell (tintinnabulum), which are carried side by side in procession at the head of the clergy on state occasions, and the cappa magna which is worn by the canons or secular members of the collegiate chapter when assisting at the Divine Office.
To this class belong just four great papal churches of Rome, which among other distinctions have a special "holy door" and to which a visit is always prescribed as one of the conditions for gaining the Roman Jubilee. Upon relinquishing the title of Patriarch of the West, Pope Benedict XVI renamed these basilicas from "Patriarchal Basilicas" to "Papal Basilicas".
These four papal or major basilicas were formerly known as "patriarchal basilicas". Together with the minor basilica of St Lawrence outside the Walls, they were by some associated with the five ancient patriarchal sees of Christendom (see Pentarchy). Thus St John Lateran was associated with Rome, St Peter's with Constantinople, St Paul's with Alexandria, St Mary Major with Antioch, and St Lawrence with Jerusalem.
There are four "pontifical" (a word that in this context means "papal") basilicas in Italy:
The title "patriarchal" is officially given to two churches associated with Saint Francis of Assisi situated in or near his home town:
The description "patriarchal" also applies to basilicas associated with bishops who have the title of patriarch, such as the Patriarchal Cathedral Basilica of St. Mark in Venice and the Patriarchal Basilica of Aquileia, which with its archaeological area is a UNESCO World Heritage Site.
The lesser minor basilicas are the vast majority, including some cathedrals, many technically parish churches, some shrines, some abbatial or conventual churches. Some oratories, semi-private places of worship, have been raised to the status of minor basilica, such as Saint Joseph's Oratory in Canada.
Notre-Dame de Québec Cathedral in Quebec City was the first basilica in North America, designated by Pope Pius IX in 1874. St. Adalbert's Basilica in Buffalo, New York was the first Basilica in the United States in 1907 by Pope Pius X. In Colombia, the Las Lajas Cathedral has been a minor basilica since 1954. Basilica of Our Lady of Peace of Yamoussoukro, in Cote d'Ivoire (West Africa) is reported slightly larger than St Peter's Basilica.
There was a pronounced tendency in the twentieth century to add to their number of churches that were granted the title of minor basilica. Examples among the many are the church containing Francisco Franco's tomb and those of many others in the monumental Valley of the Fallen near Madrid, the Mission San Carlos Borromeo de Carmelo, in Carmel, California (USA), Manila Cathedral, also known as the Minor Basilica of the Immaculate Conception in Intramuros, or the original Spanish settlement of Manila, and the Mission Basilica San Juan Capistrano. Towards the end of that century stricter rules were applied and it was decided, for instance, that since cathedrals outrank basilicas in any case, the title of minor basilica would no longer be granted to them.
The papal or major basilicas outrank in precedence all other churches. Other rankings put the cathedral (or co-cathedral) of a bishop ahead of all other churches in the same diocese, even if they have the title of basilica. If the cathedral is that of a suffragan diocese, it yields precedence to the cathedral of the metropolitan see. The cathedral of a primate is considered to rank higher than that of a metropolitan. Other classifications of churches include collegiate churches, which may or may not also be minor basilicas.