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)