In the Roman Canon, after Clement, we find Sixtus.
The name of Xystus, found in ancient records, is the Greek form of Sixtus. During the first three centuries, there were two Popes of this name. Sixtus I (115 to about 125) governed the Church during the reign of the Emperor Hadrian, when the lot of the Christians was a hard and painful one; he suffered martyrdom and was buried in the Vatican near St. Peter. His feast occurs on the sixth of April.
Far better known and more celebrated is Sixtus II, a Greek by birth. His pontificate (257-258) fell during the stormy period of the Valerian persecution of the Christians. In spite of the Emperor’s prohibition, he ventured to hold divine service in the Catacombs. Discovered by the heathen soldiers and apprehended, he was dragged into the city before the tribunal and condemned; afterward he was again led back to the Catacomb of Praetextatus, in which he had previously celebrated the Holy Sacrifice, and was beheaded on, or near his episcopal throne. The crown of martyrdom was granted to him on August 6, 258. His body now rests in the very ancient church situated on the Appian Way, S. Sisto vecchio in Rome.
Which Sixtus is it — the first or the second — that is commemorated in the Canon? Opinions are divided. To prove that Sixtus I is intended, it is asserted that the five Popes are mentioned in chronological order. As only Sixtus I reigned before Cornelius, he is mentioned in the Canon in that position.
More and stronger reasons are in favor of Sixtus II. His memory has ever been highly celebrated in the Church; the Catacombs prove this by many pictures, illustrations, and prayers. As Sixtus II, in his martyrdom, preceded his glorious Deacon Lawrence, thus is he likewise mentioned before him in the Canon. St. Sixtus II, it is true, occupied the Papal chair only after St. Cornelius; but here there was a reason for departing from the chronological order and placing the name of Sixtus before that of Cornelius. For this was done that the names of the two Saints, Cornelius and Cyprian, might not be here separated, as they were otherwise always connected in the veneration of the Church. Already in the most ancient Roman liturgy both have a common Mass, as is still the case at the present day.
St. Sixtus, pray for us!
For the Greater Glory of God,