I am reposting this post from 2011.
The Chair of Saint Peter is a relic conserved in St. Peter's Basilica, Rome, enclosed in a gilt bronze casing that was designed by Gian Lorenzo Bernini. This grandiose sculpture monument was created to enclose the wooden chair of St Peter. The chair on which, according to ancient tradition, St. Peter sat and taught Roman Christians. The four statues flanking the throne are Doctors of the Church, St. Ambrose, St. Anthanasius (left); and St. John Chrysostom, St. Augustine (right). The fine alabaster window above shows the Holy Spirit as a dove. Above the Chair are two angels bearing the tiara and keys, symbols of the Roman pontiff's authority. On the Chair, are three bas-reliefs picked out in gold, which refer to the same number of Gospel episodes: the Consignment of the keys, Feed my sheep, and the Washing of the feet.
The chair or cathedra of Peter symbolizes the perpetual continuity of the doctrine and its promise of infallibility. It triumphed over all heresies throughout the centuries.
O God, the Shepherd and Ruler of all Your faithful people, mercifully look upon Your servant Pope Benedict XVI, whom You have chosen as the chief Shepherd to preside over Your Church. We beg You to help him edify, both by word and example, those over whom he has charge, that he may reach everlasting life together with the flock entrusted to him. Through Christ our Lord. Amen.