There you go.
It occurred at the reformation.
Well, then, I can only conclude you haven’t done your homework on Church history, because you’re then left to explain why the doctrine of purgatory has been taught in the Church implicitly since at least the 2nd century and explicitly since at least the 4th. I’ll start with a few of the more explicit teachings of one of the most well known Church Fathers and then work my way up from the earliest documents:
***“Temporal punishments are suffered by some in this life only, by some after death, by some both here and hereafter, but all of them before that last and strictest judgment. But not all who suffer temporal punishments after death will come to eternal punishments, which are to follow after that judgment” ***(Augustine of Hippo, The City of God 21:13 [A.D. 419]).
"That there should be some fire even after this life is not incredible, and it can be inquired into and either be discovered or left hidden whether some of the faithful may be saved, some more slowly and some more quickly in the greater or lesser degree in which they loved the good things that perish, through a certain purgatorial fire." (Handbook on Faith, Hope, and Charity 18:69 [A.D. 421]).
“The citizen of a prominent city, I erected this while I lived, that I might have a resting place for my body. Abercius is my name, a disciple of the chaste Shepherd who feeds his sheep on the mountains and in the fields, who has great eyes surveying everywhere, who taught me the faithful writings of life. Standing by, I, Abercius, ordered this to be inscribed: Truly, I was in my seventy-second year.** May everyone who is in accord with this and who understands it pray for Abercius.**” (Epitaph of St. Abercius [A.D. 190]).
“[T]hat very night, this was shown to me in a vision: I [Perpetua] saw Dinocrates going out from a gloomy place, where also there were several others, and he was parched and very thirsty, with a filthy countenance and pallid color, and the wound on his face which he had when he died.** This Dinocrates had been my brother after the flesh, seven years of age, who died miserably with disease. . . . For him I had made my prayer, and between him and me there was a large interval, so that neither of us could approach to the other . . . and * I knew that my brother was in suffering. But I trusted that my prayer would bring help to his suffering; and I prayed for him every day*** until we passed over into the prison of the camp, for we were to fight in the camp-show. Then . . . I made my prayer for my brother day and night, groaning and weeping that he might be granted to me. Then, on the day on which we remained in fetters, this was shown to me: I saw that the place which I had formerly observed to be in gloom was now bright; and Dinocrates, with a clean body well clad, was finding refreshment. . . . [And] he went away from the water to play joyously, after the manner of children, and I awoke. Then I understood that he was translated from the place of punishment” (The Martyrdom of Perpetua and Felicity 2:3–4 [A.D. 202]).
“A woman, after the death of her husband . . . prays for his soul and asks that he may, while waiting, find rest; and that he may share in the first resurrection. And each year, on the anniversary of his death, she offers the sacrifice” (Tertullian, Monogamy 10:1–2 [A.D. 216]).
“It is one thing to stand for pardon, another thing to attain to glory; it is one thing, when cast into prison, not to go out thence until one has paid the uttermost farthing; another thing at once to receive the wages of faith and courage. It is one thing, tortured by long suffering for sins, to be cleansed and long purged by fire; another to have purged all sins by suffering.** It is one thing, in fine, to be in suspense till the sentence of God at the day of judgment; another to be at once crowned by the Lord**” (Cyprian of Carthage, Letters 51[55]:20 [A.D. 253]).
“Then we make mention also of those who have already fallen asleep: first, the patriarchs, prophets, apostles, and martyrs, that through their prayers and supplications God would receive our petition; next, we make mention also of the holy fathers and bishops who have already fallen asleep, and, to put it simply, of all among us who have already fallen asleep,
for we believe that it will be of very great benefit to the souls of those for whom the petition is carried up, while this holy and most solemn sacrifice is laid out” (Cyril of Jerusalem, Catechetical Lectures 23:5:9 [A.D. 350]).
"If a man distinguish in himself what is peculiarly human from that which is irrational, and if he be on the watch for a life of greater urbanity for himself, in this present life he will purify himself of any evil contracted, overcoming the irrational by reason. If he has inclined to the irrational pressure of the passions, using for the passions the cooperating hide of things irrational, he may afterward in a quite different manner be very much interested in what is better, when,
after his departure out of the body, he gains knowledge of the difference between virtue and vice and finds that he is not able to partake of divinity until he has been purged of the filthy contagion in his soul by the purifying fire."** (Greogry of Nyssa, Sermon on the Dead [A.D. 382]).