The Greater Litanies

On this day there used to be celebrated at Rome the Robigalia, which were replaced in later days by the Christian procession that passed along the Via Flaminia to the Milvian Bridge and from there to St. Peter’s. Consequently the feast of St Mark the Evangelist was not regularly inserted in the Roman Calendar until about the twelfth century. This delay is all the more surprising because Mark was among the first heralds who, together with Peter, brought the glad tidings to Rome. Moreover, he wrote his Gospel in the Eternal City, at the request of the Romans themselves, and when, some time afterwards, Paul suffered there his first imprisonment, Mark, together with Luke, gave him the same devoted help as he had given to the Prince of the Apostles.
On this day the Greater Litanies conclude with the stational Mass at St. Peter’s. The procession is, therefore, in no way related to the feast of St Mark; so far is this from being the case that, when the feast is transferred to another day, the Greater Litanies are not likewise transferred. The only exception is for Easter Sunday; because if it should fall on April 25, the procession would then take place on the following Tuesday.

Why did St Gregory choose April 25 for a procession and Station in which everything reminds us of compunction and penance, and which would seem so out of keeping with the joyous season of Easter? The first to give a satisfactory answer to this difficulty was Canon Moretti, a learned liturgist of the 18th century. In a disertation of great erudition, he proves that in the 5th, and probably even in the 4th century, April 25th was observed at Rome as a day of great solemnity. The faithful went, on that day, to the Basilica of St Peter, in order to celebrate the anniversary of the first entrance of the Prince of the Apostles into Rome, upon which he thus conferred the inalienable privilege of being the capital of Christendom. It is from that day that we count the 25 years, 2 months and some days that St Peter reigned as bishop of Rome. The Sacramentary of St Leo gives us the Mass of this solemnity, which afterwards ceased to be kept. St Gregory was anxious to perpetuate the memory of a day which gave to Rome her grandest glory.
In the Middle Ages all recollection of the Robigalia had entirely passed away in Rome, together with the traditional route of the classic procession of the Roman youth along the Via Flaminia. Therefore the procession with the Litanies was accustomed to proceed from the Lateran to the Basilica of St Mark, and thence towards St. Peter’s, this rule continuing in force until the latter half of the nineteenth century.