Which cathedral is the official ecclesiastical seat of the Bishop of Rome?

The Archbasilica of Saint John Lateran is the official ecclesiastical seat of the Bishop of Rome.

Although St. Peter’s Basilica is more famous internationally, Saint John Lateran is Rome’s cathedral and the pope’s cathedral as Bishop of Rome. Its full title is the Archbasilica Cathedral of the Most Holy Savior and of Saints John the Baptist and John the Evangelist in the Lateran.

The basilica originated in the early fourth century under Emperor Constantine, on land associated with the Lateran family. It has been rebuilt and altered several times because of earthquakes, fires, neglect, and changing architectural styles.

The building is one of the four major papal basilicas in Rome. Its position as the pope’s cathedral is a common point of confusion: the Vatican’s St. Peter’s Basilica is the pope’s principal pilgrimage church, but it is not Rome’s cathedral.