My interest is more in looking at what has been taught throughout history and what may have influenced their understanding. I believe that the actual letter was received with less mystery by the original audience, but it is clear that at least by the time of Irenaeus (without any question Cyprian) the view was that the Church was experiencing the actual Tribulation of Revelation.
Could you provide some references to this belief?
I found some references in Cyprian's Epistles and Treatises, that he believed all believers experience tribulation (pretribulational dispensationalists today believe this too), but not specifically the great tribulation of the apocalypse.
"Shall tribulation, or distress, or persecution, or famine or nakedness, or peril, or sword? (Rom. 8:35) None of these things can separate believers, nothing can tear away those who are clinging to His body and blood" (The Epistles of Cyprian, Epistle VII, 5)
"Let each one of us pray God not for himself only, but for all the brethren, even as the Lord has taught us to pray, when He bids to each one, not private prayer, but enjoined them, when they prayed, to pray for all in common prayer and concordant supplication. If the Lord shall behold us humble and peaceable; if He shall see us joined one with another; if He shall see us fearful concerning His anger; if corrected and amended by the present tribulation, He will maintain us safe from the disturbances of the enemy. Discipline hath preceded; pardon also shall follow" (The Epistles of Cyprian, Epistle VII, 7)
"When, therefore, weakness and inefficiency and any destruction seize us, then our strength is made perfect; then our faith, if when tried it shall stand fast, is crowned; as it is written, “The furnace trieth the vessels of the potter, and the trial of tribulation just men.” (Sirach 27:5) This, in short, is the difference between us and others who know not God, that in misfortune they complain and murmur, while adversity does not call us away from the truth of virtue and faith, but strengthens us by its suffering" (The Treatises of Cyprian, Treatise VII, 13)
Epistle XV, 2; Epistle XX, 2; Treatise IX, 12-13; Treatise XI; etc.
In Epistle XXI, section 2, Cyprian even links the tribulation experienced by Christians to that meted out by the Roman emperors, but never mentions the apocalypse of John. In Epistle XXV, section 4 Cyprian references a verse in the apocalypse, Ch. 3 verse 21, viz.
the one who overcomes will be granted regal rights, to spur on the persecution suffered by Christians, but this is a really sloppy foundation for your position, because he also references Romans 8:35, and present day dispensationalists don't deny that Revelation 3:21 is speaking to Christians today.
In Treatise XI, On the Exhortation to Martyrdom, section 11, at the end of his sermon on persevering through tribulation experienced by every saint, referencing saints in old testament times, Cyprian references the apocalypse, Rev. 7:9-15, as referring to Christian martyrs, but he never explicitly states that his audience, or himself, were the Christian martyrs of Rev. 7:9-15 (which is what you are claiming). I do believe that the ekklesia will exist on earth in the 70th week of daniel and that the saints in the 70th week of daniel will be Christians. And even if I didn't believe this, Cyprian's explicit pretribulationalism quote(s), as I have referenced in the OP (of the other thread), cannot be ignored. Not to mention the fact that probably most modern dispensationalists would also see these Revelation 7:9-15 tribulation saints as Christians, but just not part of the ekklesia.
In Treatise XII, Third Book, section 6, in another sermon on the same subject, he never references the apocalypse. In section 16 of the same reference, he mentions the apocylpse, but again, never explicitly states that he or his audience were the Christians experiencing the tribulation mentioned, as you claimed.
If you are going to argue that his reference to the apocalypse proves that he believed that his audience was experiencing the great tribulation of the apocalypse, the 70th week of Daniel, then you also must claim that Cyprian believed that his audience was the persecuted Abel, Zacharias the martyr-priest, David, Elijah and etc. This is the context in which he referenced the apocalypse.
As for Iranaeus, I couldn't find anything that states what you claimed.