Symbolum Gaenswinianum:

[to be sung at the end of Prime on the Feast of the Confustification. Because Prime is a minor hour, this antiphon is always semidoubled. If the Feast of the Confustification is celebrated in Eastertide, two Alleluias (which are really only one Alleluia) are added to the end.]

And the Catholic faith is this: That we have one Petrine Ministry;
Neither confounding the persons nor dividing the office;
For there is one person of Francis, and another of Benedict,
But the ministry of Francis and Benedict is all one, the glory equal, the majesty temporary.
Such as Francis is, such is Benedict,
Francis elected, Benedict elected,
Francis incomprehensible, Benedict incomprehensible,
Francis temporary, Benedict temporary.
And yet they are not two temporaries but one temporary.
As also there are not two electeds nor two incomprehensibles, but one elected and one incomprehensible.
So likewise Francis is infallible and Benedict infallible,
And yet they are not two infallibles, but one infallible.
So Francis is Pope, Benedict is Pope,
And yet they are not two Popes but one Pope.
So likewise Francis is Vicar, Benedict is Vicar,
And yet they are not two Vicars but one Vicar.
For like as we are compelled by the Christian verity to acknowledge each prelate to be Pope
So are we forbidden by the Catholic religion to say; There are two Popes or two Vicars.