The Great Monarch, the "Warning" and the Duration of the Period of Peace

 From Unveiling the Apocalypse:

One of the oldest prophecies of the Great Monarch is found in the Apocalypse of Methodius, which also foretells the appearance of the sign of the cross before the Last Judgement. Ironically, this prophecy is also related to the central subject matter of Christine Watkins' book The Warning: Testimonies and Prophecies of the Illumination of Consciences, which has recently popularised Mallett and O'Connor's writings due to her endorsement of the Countdown to the Kingdom website:

…the Cross on which our Lord Jesus Christ hung for the common salvation of all will begin to appear before him at his coming to convict the lack of faith of unbelievers… When the Cross has been lifted up on high to heaven, the king of the Romans will directly give up his spirit. Then every principality and power will be destroyed that the Son of Perdition may be manifest.

According to Church Tradition, the Great Monarch will bring about the restoration the Church after a period of desolation, which I argue in my book Unveiling the Apocalypse: The Final Passover of the Church, is related to the current apostasy we are experiencing due to the period of the unbinding of Satan at the end of the "thousand years". After the Great Monarch brings about the renovation of the Church, the prophetic tradition tells us that he will lay down his crown on the Mount of Olives just immediately before the appearance of the Antichrist:

Some of our teachers say that a King of the Franks will possess the entire Roman Empire. He will be the greatest and last of all Monarchs. After having wisely governed his kingdom, he will go into Jerusalem and will lay his sceptre and his crown upon the Mount of Olives. Immediately afterwards, Antichrist will come. (Adso of Montier-en-Der, De ortu et tempore Antichristi)                                        

The only Church approved private revelation to give some indication of the duration of the period of peace is Melanie's 1849 version of the Secret of La Salette, which explicitly states that this period of renewal will not last long before the appearance of the Antichrist, and similarly connects the period of the restoration of the Church with the reign of the Great Monarch...(Read more.)

More HERE.

 Here is a really interesting interview with author Charles Coulombe in  which the Great Monarch is mentioned.