The reason why the Roman Catholic Church developed the doctrine of purgatory was twofold, I think: the ancient Patristic doctrine which one finds echoes of in books like The State of the Soul After Death by Fr. Seraphim Rose, but which is also remarkably difficult to put into words, is a very frightening concept compared to Purgatory, as the Patristic position is that we cannot be sure even of our own salvation; the only certain way of obtaining salvation being martyrdom, for example, by the Roman Pagans or later the Saracens. Once-saved, always-saved was an unknown concept in antiquity. Indeed, it was for this reason, St. Anthony sought to follow the example of our Lord; on inheriting the vast wealth ot his parents, he sold some of it to set up a trust fund to provide for his sister, gave the rest of it, a vast amount of money, the majority of it in fact, to the poor, and then actively sought martyrdom, dressing in white and attempting to obstruct Imperial Roman processions, where Christians were being led to the arena to be killed, however, the soldiers on each occasion merely shoved him out of the way, and thus he began his monastic career. His life story, including his struggled with delusion and his Wagnerian struggle with the devil, and years later, his meeting the first desert father, the mysterious and gentlr saint known as Paul the Hermit, who St. Anthony discovered living in a desert oasis sustained by friendly animals, a man truly living on God, is detailed in the book Vita Antonis by St. Athanasius of Alexandria, a book every Christian should read, remembering that it was St. Athanasius who, as a deacon, led the prosecution of Arius at the Council of Nicea in 325 on behalf of the aged Alexandrian Pope St. Alexander*, and then when he became Pope and Patriarch of Alexandria and All Africa** made the final determination as to the canon of the New Testament, and defended and preserved the Trinitarian faith against the opposition of the Roman Empire, which repeatedly exiled him and tried to silence him so that Arianism could take over. The other major book by St. Athanasius is De Incarnatione, which is an explanation of the doctrine of the Incarnation, much esteemed by CS Lewis. The second reason I think Rome promulgated the doctrine of Purgatory, aside from watering down a Patristic doctrine that many people found too frightening, a doctrine which the increasingly poorly catechized Roman priests could not deal with (with the exception of learned scholastics at some of the Benedictine monasteries, such as the Cluniac monasteries and those which later were unfortunately secularized to become the universities of Oxford and Cambridge, and after around 1200, the Dominican, Fransiscan and Carmelite friars and Norbertine canons, known in colloquial English as Blackfriars, Greyfriars, Magpies and Whitefriars; the excellence of these clergy in the sea of incompetent pre-Tridentine secular parish priests doubtless caused many to join monasteries, and still others to affiliate with parishes and peculiar churches*** operated by the Dominicans, Fransiscans, and other friars), was rather cynical. So rather than addressing the root problem of theologically illiterate priests who were not competent pastors and could not help the faithful through the process of what St. Paul says we must do, which is to work out our salvation with fear and trembling, Rome took a cynical approach, redefining the process of Particular Judgement, declaring that souls which otherwise would dwell in Hades before the general resurrection would henceforth be considered to remain in Purgatory, and implemented indulgences. Indulgences turned into a major financial boon for the Roman Church once corrupt popes (starting, I believe, during the Avignon Schism) began exploiting them, with Leo X taking the practice to an extreme in order to finish St. Peter’s Basillica and repair the damage caused by the troops of Emperor Charles V having sacked Rome (for I think the third time since the Lombards sacked Rome around 600 AD). But even before that time, the system of purgatory and indulgences had been a financial boon for priests, as frightened people of means would endow chantries, where priests would be employed to say requiem masses and the office of the dead and other prayers for their benefit, or in the case of some better intentioned persons, for the benefit of others. Now, this could actually have been turned into something positive, had wealthy people been encouraged to endow benefices, or if the chantries had functioned as chapels of ease within a parish, and indeed I believe many did. Alas, parish boundaries themselves had become highly political, and remain so even today in England (witness the ceremony of Beating the Bounds on Rogation Days; this is important because some land within a parish has attached to its title easements requiring the owner to pay for maintenance on the parish church; I would assume a similiar system exists with parish kirks in Scotland, or did so at one time likewise exist). * Pope St. Alexander was severely tortured by the Romans under Diocletian due to his faith, but he lived to an old age, and St. Athanasius was his protodeacon, his chief aid at Nicea, and his successor. The outrage of St. Alexander of Alexandria over the teaching of Arius, and the still greater outrage of St. Nicholas of Myra (a bishoproughly the same age as St. Alexander, and also known to have been tortured for being Christian; forensic analysis of his skeleton says that his nose was broken at least three times, became so enraged by the heresy of Arius during the procedings of the Council of Nicea that he slapped him, causing him to be automatically deposed under the ancient canon law prohibiting clergy from hitting anyone, but who was then pardoned by Emperor Constantine after begging the forgiveness of the council, and restored to his office) , who together with St. Basil the Great, is one of two ancient bishops who inspired the figure of Sinterklaas, helps to validate the antiquity of the Trinitarian faith and refute the idea we see hinted at in Dr. Rowan Williams book on Arius, that consubstantiality was a doctrinal innovation made at Nicea. ** As I have said elsewhere on the forum, the Bishops of Rome were only called Pope starting in the sixth century, and only began to claim super-episcopal powers starting in the ninth century. Before the sixth century, the only bishops styled as Pope were the Patriarchs of Alexandria and All Africa; the Alexandrian Popes have never claimed universal jurisdiction or suggested they are infallible, but to the chagrin of Roman Catholics, Pope St. Athanasius is more important to the theology of the Christian church than any Roman bishop called Pope. I suspect jealousy of the influence wielded by the Pope of Alexandria played into the animosity between Archbishop Leo and Pope Dioscorus. *** By peculiar church, I mean a church operated directly by friars which overlapped parish boundaries. In England today there are a number of Peculiars, which consist either of churches under the jurisdiction of the Archbishop of Canterbury despite being in a different diocese, or Royal Peculiars under the direct control of the Crown, most notably, St. George’s Chapel, Windsor, the two chapels in the Tower of London, the Queen’s Chapel of the Savoy, next to the Savoy Hotel and Savoy Theatre (both built by impressario Richard Doyle Carte, who financed the operettas of Gilbert and Sullivan; Sir Arthur Sullivan also composed many beautiful hymns such as Onward Christian Soldiers), and most famous of all, the Collegiate Church of St. Peter, better known as Westminster Abbey.