I just came back on to say, I am not even sure that these prophecies or "prophecies" began with a Sibyl. I don't have a sure Catholic source for that.
So just ignore everything I've said except to be very wary and research each supposed prophecy.
I am getting much more advanced in Latin now and could translate Holzhauser, that may help me, in case he cites sources for his belief in the Great Monarch. But I read slowly and painfully, having to look up many words, and that is not where I want to spend my energy. I am not preoccupied with this topic anymore.
PereJoseph, from what I recall, Anna-Maria Taigi prophesizes a future Pope and the Three Days of Darkness or something like it, but not a Great Monarch, and it is by free-association that people tack the Monarch onto that. ( There is lots of free-association going on with this topic ). Elisabetta Canori-Mora, I believe, also prophesizes a Pope but no Great Monarch. And if a prophecy mentions a king that doesn't mean it is the GREAT Monarch, but again, people read him into everything whenever a future great king is mentioned.
Do not take my word for all this, I am fuzzy on the details. Do your own research. But the Taigi and Canori-Mora prophecies stuck me as quite authentic when I was on this track, and I am almost positive they did not mention a Great Monarch, though one or both mentions a future Pope. That is what I now believe, there will be a future Pope who may be the restrainer, and there may be kings in Europe again, but not a Great Monarch.
The Great Monarch idea fits all too neatly into sinister currents I see happening in France, and I am definitely on my guard here.