Gregorian Masses are a series of thirty consecutive Holy Masses celebrated by a priest for the eternal rest of a departed soul, for this soul‘s release from purgatory.
They take their name from Pope Saint Gregory the Great (540-604) who established this practice. He tells us in his Dialogues how a monk called Justus was freed from purgatory by means of thirty Holy Masses offered up for him:
“Here also I cannot but tell you that which happened three years since in mine own Monastery. A certain monk there was, called Justus, one very cunning in medicine, and whiles I remained in the Abbey, served me very diligently, attending upon me in my often infirmities and sickness. This man himself at length fell sore sick, so that in very deed he was brought to the last cast. A brother he had, called Copiosus, that had care of him, who yet liveth. Justus perceiving himself past all hope of life, told this brother of his where he had secretly laid up three crowns of gold; but yet they were not so closely conveyed, that they could be concealed from the monks: for they, carefully seeking, and tossing up all his medicines and boxes, found in one of them these three crowns hidden. Which thing so soon as I understood, very much grieved I was, and could not quietly digest so great a sin at his hands, that lived with us in community, because the rule of my Monastery was that all the monks thereof should so live in common, that none in particular might possess anything proper to himself. Being, therefore, much troubled and grieved at that which had happened, I began to think with myself what was best to be done, both for the soul of him that was now dying, and also for the edification and example of those that were yet living. At length I sent for Pretiosus, Prior of the Monastery, and gave him this charge: ‘See,‘ quoth I, ‘that none of our monks do so much as visit Justus in this his extremity, neither let any give him any comfort at all: and when his last hour draweth nigh, and he doth desire the presence of his spiritual brethren, let his carnal brother tell him that they do all detest him, for the three crowns which he had hidden: that, at least before his death, sorrow may wound his heart, and purge it from the sin committed: and when he is dead, let not his body be buried amongst the rest of the monks, but make a grave for him in some one dunghill or other, and there cast it in, together with the three crowns which he left behind him, crying out all with joint voice: ‘Thy money be with thee unto perdition’; and so put earth upon him.‘
Saint Gregory the Great: Dialogues, Book 4, Chapter 55
In either of which things my mind and desire was, both to help him that was leaving the world, and also to edify the monks yet remaining behind, that both grief of death might make him pardonable for his sin, and such a severe sentence against avarice might terrify and preserve them from the like offence: both which, by God’s goodness, fell out accordingly. For when the foresaid monk came to die, and carefully desired to be commended to the devotions of his brethren, and yet none of them did either visit him, or so much as speak to him: his brother Copiosus told him for what cause they had all given him over: at which words he straightways sighed for his sin, and in that sorrow gave up the ghost. And after his death, he was buried in that manner, as I had given in commandment: by which fact all the monks were so terrified, that they began each one to seek out the least and basest things in their cells, and which by the rule they might lawfully keep: and very much they feared, lest some thing they had, for which they might be blamed.
Thirty days after his departure, I began to take compassion upon him, and with great grief to think of his punishment, and what means there was to help him: whereupon I called again for Pretiosus, Prior of my Monastery, and with an heavy heart spake thus unto him: ‘It is now a good while since that our brother which is departed remaineth in the torments of fire, and therefore we must shew him some charity, and labour what we may to procure his delivery: wherefore go your way, and see that for thirty days following sacrifice be offered for him, so that no one day pass in which, for his absolution and discharge, the healthful sacrifice be not offered‘: who forthwith departed, and put my commandment in execution. In the mean time, my mind being busied about other affairs, so that I took no heed to the days how they passed: upon a certain night the same monk that was dead, appeared to his brother Copiosus: who, seeing him, enquired of his state in this manner: ‘What is the matter, brother? and how is it with you?‘ to whom he answered thus: ‘Hitherto have I been in bad case, but now I am well; for this day have I received the communion‘: with which news Copiosus straightways coming to the Monastery, told the monks: and they diligently counting the days, found it to be that in which the thirtieth sacrifice was offered for his soul: and so, though neither Copiosus knew what the monks had done for him, nor they what he had seen concerning the state of his brother, yet at one and the same time both he knew what they had done, and they what he had seen, and so the sacrifice and vision agreeing together, apparent it was that the dead monk was by the holy sacrifice delivered from his pains.“
Saint Gregory the Great, pray for us!