Here is some chant for today's feast: the traditional Alleluia and Verse for the Feast.
And here is some polyphony: three contrasting settings of the Tu es Petrus.
The first is possibly the most famous, by Palestrina. The second is by one of my favourite modern composers, Maurice Duruflé. The third is by James Macmillan, at the Papal Mass in Westminster Cathedral.
Happy Feast Day!
Tu es Petrus et super hanc petram ædificabo ecclesiam meam et portæ inferi non prævalebunt adversus eam. Et tibi dabo claves regni cælorum.
Thou art Peter and upon this rock, I will build my Church, and the gates of hell will not prevail against her; and I will give you the keys of the kingdom of heaven.
Remember to pray for our Holy Father, Pope Francis, and also for his predecessor, Pope Emeritus Benedict XVl today - and every day.