Ember Friday in Advent was the original date for this feast. The celebration by the Greeks on July 2 of the placing of the robe of the Blessed Virgin in the Basilica of Blachernae (A.D. 469) became in the Latin church the commemoration of the visit of Mary to the home of Zachary and Elizabeth. It was kept by the Franciscans as early as 1263; the Council of Basil (1431) made it a holy day of obligation.
Sts. Processus and Martinian were the keepers of the Mamertine prison, during the imprisonment of Sts. Peter and Paul, by whom they were converted. Like them they suffered martyrdom under Emperor Nero. Their relics now repose in St. Peter’s; during the Vatican Council the papal throne occupied by Pius IX stood at the tomb of these two gaolers of the Princes of the Apostles. (Source: The New Roman Missal, Rev. F. X. Lasance)