Today offer a prayer of protection for our Church and it's journey ahead:

Grant, we pray, almighty God
that no tempest may disturb us, for you have set us fast on the rock of the Apostle Peter's confession of faith.

Through our Lord Jesus Christ, your Son, 
who lives and reigns with you in the unity of the Holy Spirit,
one God, for ever and ever.
Amen.

According to Pope Benedict:

The "Chair of St Peter" is a very ancient tradition, proven to have existed in Rome since the fourth century. On it we give thanks to God for the mission he entrusted to the Apostle Peter and his Successors.

"Cathedra" literally means the established seat of the Bishop, placed in the mother church of a diocese which for this reason is known as a "cathedral"; it is the symbol of the Bishop's authority and in particular, of his "magisterium", that is, the evangelical teaching which, as a successor of the Apostles, he is called to safeguard and to transmit to the Christian Community. . . .
 
The See of Rome, after St Peter's travels, thus came to be recognized as the See of the Successor of Peter, and its Bishop's "cathedra" represented the mission entrusted to him by Christ to tend his entire flock. . . .
 
Celebrating the "Chair" of Peter, therefore, as we are doing today, means attributing a strong spiritual significance to it and recognizing it as a privileged sign of the love of God, the eternal Good Shepherd, who wanted to gather his whole Church and lead her on the path of salvation [ General Audience, Feb. 22, 2006].