The Basilica of Saint John Lateran is the official ecclesiastical seat of the Pope and the oldest of the 5 ranking basilicas in Rome.
The site on which the basilica sits was originally occupied by the palace of the Lateran family during the early Roman empire until Nero confiscated the property after accusing the Laterans of conspiracy against the emperor.
The Palace fell into the hands of Emperor Constantine and later given to the Bishop of Rome as a gift. The precise Date is unknown but is calculated to have been during the pontificate of Pope Miltiades in 313. the palace was converted and enlarged to eventually become the Cathedral of Rome, and the seat of all Popes.
The official dedication of the Lateran Palace and basilica took palace during the papacy of Pope Sylvester in 324. In reflection of the basilica's primacy in the world as mother church, the words Sacrosancta Lateranensis ecclesia omnium urbis et orbis ecclesiarum mater et caput are incised across the façade, meaning "Most Holy Lateran Church, of all the churches in the city and in the world, the mother and head".
The Lateran Palace and Basilica were rededicated to Saint John the Baptist, in honor of the newly consecrated basilica, in the 10th century by Pope Sergius III and in the 12th century, Pope Lucius II dedicated them to Saint John the Evangelist. The church became the most important shrine in honor of the two saints and in later years a Benedictine monastery was established at the Lateran as a devotional to the two saints.
In 1309, the French Pope Clement V made the decision of transferring the official seat of the Church to Avignon in southeastern France, where it remained until 1377.
It was during this time that the Lateran Palace and basilica began its decline. It was hit by two rampaging fires in 1307 and again in 1361. The Avignon papacy however sent money to their bishops in Rome to pay for the reconstruction but despite the gesture to help, the Palace and basilica had lost their original splendor. When the Avignon papacy formally ended in 1377 and brought back to Rome, the Palace and basilica were deemed inadequate for residency and the popes instead took residency at the Basilica of Santa Maria in Trastevere and later at the Basilica of Santa Maria Maggiore until the new Palace of Popes was built at the Vatican where the papacy remains today.
The Lateran Palace and Basilica were rebuilt in 1586, during the papacy of Pope Sixtus the V and it was then that they became separate entities.
Over the course of centuries, several pontifixes made changes and additions to the structures.
The architect Domenico Fontana oversaw much of the project and the interiors were done under the direction of Francesco Borromini by the order of Pope Innocent X for the occasion of the Jubilee in 1650. Later Pope Clement XII launched a competition to design a new facade and the winner was Alessandro Galilei. The façade, made out of travertine, completed in 1735, left no visible evidence of its original basilica architecture.
Pio IX and Leone XIII had reconstruction and restoration works executed in its presbytery and apse by Virginio Vespignani. On its balustrade you can admire 15 gigantic statues (7 metres high) representing Saints and the Redeemer's one being the central of them. In its left porch, you can see the Constantine's statue coming from the "Terme Imperiali del Quirinale". The great central door, through which you can enter this basilica, has precious bronze leaves. The last door on the right, is the Holy Door which, like Saint Peter's one, is open only on the occasion of Jubilees.
Inside, the church is in a Latin cross and has five aisles. To be admired are the ceilings in gold and the beautiful floors. Under the great triumphal arch at the end of the largest nave, find the papal altar containing the elegant tabernacle, dating back to the middle of the IV century, with frescoes attributed to Barna from Siena. Also found in the tabernacle are the relics of the heads of Saint Peter and Saint Paul, kept in precious silver containers. In the nave behind the forst pillar on the right, a fragment of the famous fresco by Giotto, representing Bonifacio VIII.
In the square in front of the Lateran Palace one can see the large Egyptian obelisk, the oldest in Rome, brought by emperor Constantine II in 357 and re-erected in this piazza in 1587.
Some remains of the original buildings may still be traced inside the city walls outside the Gate of St. John, and a large wall decorated with paintings was uncovered in the 18th century within the basilica itself, behind the Lancellotti Chapel. An apse lined with mosaics and open to the air still preserves the memory of one of the most famous halls of the ancient palace, the "Triclinium2 of Pope Leo III, which was once the banquet hall of the state.
The existing structure is not ancient, but it is possible that some portions of the original mosaics have been preserved in a three-part mosaic: in the centre Christ gives their mission to the Apostles, on the left he gives the keys to St. Sylvester and the Labarum to Constantine, while on the right St. Peter gives the papal stole to Leo III.
A few traces of older buildings also came to light during the excavations made in 1880, when the work of extending the apse was in progress, but nothing more of real value or importance was discovered.
Today the Lateran Palace is home to the Pontifical Museum of Christian Antiques.