The Cathedral of the Most Holy Savior and of Saints John the Baptist and the Evangelist in the Lateran, (Italian: Santissimo Salvatore e Santi Giovanni Battista ed Evangelista in Laterano) – also known as the Papal Archbasilica of St. John [in] Lateran, St. John Lateran, or the Lateran Basilica – is the cathedral church of the Diocese of Rome in the city of Rome, Italy and therefore houses the cathedra, or ecclesiastical seat, of the Bishop of Rome, the Pope.
It is the oldest and highest ranking of the four papal major basilicas, giving it the unique title of "archbasilica". Because it is the oldest public church in the city of Rome, it is the oldest and most important basilica of the Western world,  and houses the cathedra of the Roman bishop, it has the title of ecumenicalmother church of the Catholic faithful.
The large Latin inscription on the façade reads: Clemens XII Pont Max Anno V Christo Salvatori In Hon SS Ioan Bapt et Evang. This abbreviated inscription translates to: "Pope Clement XII, in the fifth year [of his Pontificate, dedicated this building] to Christ the Savior, in honor of Saints John the Baptist and [John] the Evangelist". The inscription indicates, with its full title (see below), that the archbasilica was originally dedicated to Christ the Savior and, centuries later, co-dedicated to St. John the Baptist and St. John the Evangelist. As the Cathedral of the Pope as Bishop of Rome, it ranks superior to all other churches of the Roman Catholic Church, including St. Peter's Basilica.
The archbasilica's Latin name is Archibasilica Sanctissimi Salvatoris ac Sancti Ioannis Baptistae et Ioannis Evangelistae ad Lateranum, which in English is the Archbasilica of the Most Holy Savior and Saints John the Baptist and John the Evangelist at the Lateran, and in Italian Arcibasilica [Papale] del Santissimo Salvatore e Santi Giovanni Battista ed Evangelista in Laterano.