Today is the Feast of Sts. Peter and Paul. I always find it remarkable that the two great apostles don’t get their own feast day, but must share it with one another. But this is as it should be: their mission was a shared one and each was intricately bound to the other. In the early Church, the bishop of Rome was most often considered the successor to both Peter and Paul, not just Peter, as both apostles “founded” the Church in Rome by their blood. For example, St. Irenaeus wrote:
Since, however, it would be very tedious, in such a volume as this, to reckon up the successions of all the Churches, we do put to confusion all those who, in whatever manner, whether by an evil self-pleasing, by vainglory, or by blindness and perverse opinion, assemble in unauthorized meetings; [we do this, I say,] by indicating that tradition derived from the apostles, of the very great, the very ancient, and universally known Church founded and organized at Rome by the two most glorious apostles, Peter and Paul; as also [by pointing out] the faith preached to men, which comes down to our time by means of the successions of the bishops. For it is a matter of necessity that every Church should agree with this Church, on account of its pre- eminent authority that is, the faithful everywhere, inasmuch as the apostolical tradition has been preserved continuously by those [faithful men] who exist everywhere. (Against Heresies, Book III, Chapter 3)
The Pope, therefore, was to continue the work of both apostles – as both the administrative head of the Church and the one who most promoted missions to all the nations. The best popes throughout history were able to do both tasks successfully.
A great book that explores both Peter and Paul’s influence on the Church of Rome is Peter and Paul in the Church of Rome: The Ecumenical Potential of a Forgotten Perspective by William Farmer and Roch Kereszty (unfortunately, it is now out of print). Kereszty is a Cistercian priest and Farmer was a Methodist when the book was written, but he later became a Catholic.
Sts. Peter and Paul, pray for us!