Major basilica (Latin: Basilica maior; plural: Basilicae maiores) is the title given to the four highest-ranking Roman Catholic church buildings, all of which are also "Papal basilicas": the Archbasilica of St. John Lateran, St. Peter's Basilica, the Basilica of St. Paul Outside the Walls, and the Basilica di Santa Maria Maggiore. All of them are located within the diocese of Rome: St. Peter's Basilica is located in Vatican City and thus within the territory and sovereign jurisdiction of the Holy See. The other three are geographically located in Italian territory, but enjoy extraterritorial status under the Lateran Treaty. The Archbasilica of St. John in the Lateran is the seat of the Pope and the site of the Papal Cathedra, and is the oldest and first in rank of the major basilicas.
All other churches that have the title of basilica are minor basilicas (Latin: basilica minor).
The title of "major basilica" was introduced in 1300 by Pope Boniface VIII. With the promulgation of the bull Antiquorum fida relatio, he instituted the Holy Year and set the conditions for its indulgences. Boniface VIII renewed certain "great remissions and indulgences for sins" which were to be obtained "by visiting the city of Rome and the venerable basilica of the Prince of the Apostles". He offered "not only full and copious, but the most full, pardon of all their sins" to those who fulfilled certain conditions: First, as truly penitent, they had to confess their sins, and, second, they had to visit on pilgrimage the basilicas of St. Peter and St. Paul, the respective burial sites of the apostles Pope St. Peter and St. Paul.