The Chair of Saint Peter is also known as the Cathedra Petri in Latin. Cathedra Petri is a relic that can be found in St. Peter's Basilica. The actual wooden chair is placed inside a beautifully sculpted bronze casing. The casing was designed by Gian Lorenzo Bernini and was built between the years 1647–53. Like in many medieval reliquaries the casing of the chair is in the form of the relic conserved inside it; meaning that it was designed by Bernini to resemble a chair. The Latin word cathedra is used for a chair or throne and denotes a chair or seat in the use of a bishop. The Chair of Peter symbolizes the office of the Pope as the Bishop of Rome.
Originally, the cathedra in St. Peter's Basilica was used by the popes. Inside the Chair is a wooden throne, which traditionally, was Saint Peter's throne. However, archeologist G.B. De Rossi, who was the last archeoligist to inspect this relic argued that only the acacia wood skeleton is in fact ancient while the other oak parts attached to the skeleton with strips of iron and ivory, are from Byzantine times.
The pattern on the upholstery of the casing depicts Christ giving the keys of heaven to St Peter. Large angelic figures were placed on both sides of a panel beneath a bronze seat cushion. The cathedra lies on bars that are held by four gigantic bronze figures; these are the doctors of the Church. The doctors are St. Ambrose and St. Augustine of the Roman Church and St. Athanasius and St. John Chrysostom of the Greek Church. The symbolism of this is That Doctors of the Church are the ones holding up the papcy and the Church.
Above the chair there is a Latin inscription: "O Pastor Ecclesiae, tu omnes Christi pascis agnos et oves" (O pastor of the Church, you feed all Christ's lambs and sheep). The same inscription was written in Greek on the right side.
Two liturgical feasts were celebrated in Rome in honor of earlier chairs associated with Saint Peter. One of these chairs was placed in the baptismal chapel of Saint Peter's Basilica, the other at the catacomb of Priscilla. No surviving chair has been identified as these more ancient chairs.
Berninis Cathedra Petri enclosing the wooden throne of St. Peter in the Vatican