The Feast of the Chair of St. Peter commemorates Christ’s choosing Peter to sit in his place as the servant-authority of the whole Church. Jesus told Peter that “you are Peter, and upon this rock I will build my church.” It is with this pastoral responsibility given him that the Pope shepherds Christ’s flock.
The wooden throne encased in bronze by Bernini was given to Pope John VIII by the Holy Roman Emperor Charles the Bald in 875.
As Pope emeritus Benedict XVI said in 2012, the Chair is "a symbol of the special mission of Peter and his Successors to tend Christ’s flock, keeping it united in faith and in charity." (vaticannews.va)