See of St Peter, Apostle (Feast)
This feast has been kept at Rome since the 4th century. It is celebrated as a symbol of the unity of the Church. The principal diocese of the Catholic Church is Rome and the Pope is its bishop. His cathedral is not, as many may be inclined to think, St Peter’s Basilica but the Church of St John Lateran. The Bishop of Rome is not ranked above other bishops but is rather primus inter pares, first among equals. The special place of the Rome diocese is because of its links with St Peter, on whom Jesus said he would build his church, and hence the unity of the Church is expressed by the solidarity of each diocese with the diocese of Rome and with each other. And when the Pope speaks formally, it is the faith of the whole Church that he proclaims and not just his own understanding of it.
From the earliest times the Church at Rome celebrated on 18 January the memory of the day when Peter held his first service with the faithful of the Eternal City. The feast of the Chair of Saint Peter at Antioch, commemorating his foundation of the See of Antioch, has also been long celebrated at Rome, on 22 February. At each place a chair (cathedra) was venerated which the Apostle had used while presiding at the Eucharist.
The Roman Church, therefore, at an early date celebrated a first and a second assumption of the episcopal office in Rome by St. Peter. This double celebration was also held in two places, in the Vatican Basilica and in a cemetery (coemeterium) on the Via Salaria. At both places a chair (cathedra) was venerated which the Apostle had used as presiding officer of the assembly of the faithful. The first of these chairs stood in the Vatican Basilica, in the baptismal chapel built by Pope Damasus. While therefore in the Vatican Basilica there stood a cathedra on which the pope sat amid the Roman clergy during the pontifical Mass, there was also in the same building a second cathedra from which the pope administered to the newly baptized the Sacrament of Confirmation. The Chair of St. Peter in the apse was made of marble and was built into the wall, while that of the baptistry was movable and could be carried. Ennodius calls the latter a sedes gestatoria. Throughout the Middle Ages it was always brought on 22 February from the above-mentioned consignatorium or place of confirmation to the high altar. That day the pope did not use the marble cathedra at the back of the apse but sat on this portable cathedra, which was, consequently, made of wood.* The importance of this feast was heightened by the fact that 22 February was considered the anniversary of the day when Peter bore witness, by the Sea of Tiberias, to the divinity of Christ and was again appointed by Christ to be the Rock of His Church (cf. John 21:15ff).
*The last pope to use this chair was Pope John XXIII. From the time of Pope Paul VI it was no longer used.