"Dearly beloved brethren, in the joy of all the holy Feast-days the whole world is partaker. There is but one love of God, and whatsoever is solemnly called to memory, if it hath been done for the salvation of all, must needs be worth the honour of a joyful memorial at the hands of all. Nevertheless, this feast which we are keeping to-day, besides that world-wide worship which it doth of right get throughout all the earth, doth deserve from this city of ours an outburst of gladness altogether special and our own. In this place it was that the two chiefest of the Apostles did so right gloriously finish their race. And upon this day whereon they lifted up that their last testimony, let it be in this place that the memory thereof receiveth the chiefest of jubilant celebrations. O Rome these twain are the men who brought the light of the Gospel of Christ to shine upon thee These are they by whom thou, from being the teacher of lies, wast turned into a learner of the truth." Sermon of St. Leo the Great, 2nd nocturn of Mattins of the feast
O Roma felix, quae duorum Principum
Es consecrata glorioso sanguine:
Horum cruore purpurata ceteras
Excellis orbis una pulchritudines.