Inspired by this LifeSite News article this is a summary of what Tyconius wrote and the comments from Pope Benedict. There is also a discussion of it at other sites.
Quotes from the article:
The bishops do, under the guise of a gift of the church, what advances the will of the devil.
Tyconius, Commentary on the Apocalypse, 4th century
[T]he Antichrist belongs to the Church, grows in it and with it until the great discessio, which initiates the final revelatio.
Joseph Ratzinger, Observations on Tyconius’ Concept of the Church, 1956
Tyconius assertions:
- The Great Apostacy – The True Believers Will Leave The Church
- Satan’s Chosen Instrument: The Bishops “The bishops do, under the guise of a gift of the church, what advances the will of the devil.”[48] The bishops offer to the beast the veneer of a lamb, while he uses them as mouthpieces for his agenda.
- The Passion of the Church
Why did Pope Benedict XVI call a heretic, Tyconius, a great theologian?
The Resignation and “A Bishop Dressed In White”
So then, consider at least some of the elements that Pope Benedict XVI had before him. As cardinal, he had already attested that the Third Secret of Fatima pertains to “the last things,” and multiple reliable sources have confirmed that it relates specifically to the great apostasy. If Benedict accepts Tyconius’ rendering of how that apostasy commences and is operating from that vantage point, might that not shed light on his bizarre and controversial “resignation?” Could his decision to “step aside” in 2013 be the result of having deciphered the Third Secret from an entirely singular outlook, influenced by his study of Tyconius? Does he view the theology of Tyconius as inextricably intertwined with Mary’s message at Fatima? And, if so, has he realized that, as Pope, he has had to initiate the “withdrawal” of the true Church from the false so as to inaugurate the great apostasy and begin the exposure of the false brethren who have infiltrated the Church to the highest of levels?
https://www.marcotosatti.com/2022/09/08/ratzinger-tyconius-and-fatima-an-interpretive-key-for-the-end-times/
The recap from the article: “Did Benedict XVI glean from the Third Secret, in accord with the teaching of Tyconius, that in God’s providential designs the climax of the confrontation between the true Church and the anti-church could only take place when the valid Successor of Peter permitted the arrival of the “bishop dressed in white”? That what was shown to the children of Fatima was exactly what Sister Lucia describes – a “mirror image” – one who appears to be the Holy Father but in fact is only a double? Was Sister Lucia additionally trying to communicate and highlight this “semblance of a pope” when she said: “[W]e had the impression that it was the Holy Father”? Did she intend to place the emphasis in that sentence on the word “impression”? – “[W]e had the impression that it was the Holy Father.” – Was this because, when the “bishop dressed in white” would finally appear, the whole world would be under that same “impression”? While, in point of fact, the bishop dressed in white would only resemble the pope, the way an image seen in a mirror resembles reality – an imitation . . . an empty reproduction . . . a usurper. If so, did this awareness lead Benedict XVI to set out in faith, like Abraham, “not knowing where he was going,”[82] handing practical power over the visible structure of the church, to a “bishop dressed in white,” so as to initiate the “great discessio”?“