Rome's papal Archbasilica of St John Lateran, or San Giovanni in Laterano, will mark its 1,700th anniversary with a year of special events starting with a Mass on 9 November. Consecrated by Pope Sylvester in 324 AD, the church is the oldest of the four main basilicas of the Eternal City, serving as the cathedral of the Diocese of Rome and the official ecclesiastical seat of the pope.

The basilica and its adjoining buildings enjoy extraterritorial status from Italy, under the 1929 Lateran Treaty which established the Vatican City as a sovereign state and regulates relations between Italy and the Catholic Church.