The idea of a letter at all, comes about from a hoax by Leo Taxil.
He was anti Masonry and mocked it; admitting to outrageous lies along the way.
“The public made me what I am; the arch-liar of the period, for when I first commenced to write against the Masons my object was amusement pure and simple. The crimes I laid at their door were so grotesque, so impossible, so widely exaggerated, I thought everybody would see the joke and give me credit for originating a new line of humour. But my readers wouldn’t have it so; they accepted my fables as gospel truth, and the more I lied for the purpose of showing that I lied, the more convinced became they that I was a paragon of veracity.
“Then it dawned upon me that there was lots of money in being a Munchausen of the right kind, and for twelve years I gave it to them hot and strong, but never too hot. When indicting such slush as the story of the devil snake who wrote prophecies on Diana’s back with the end of his tail, I sometimes said to myself: ‘Hold on, you are going too far,’ but I didn’t. My readers even took kindly to the yarn of the devil who, in order to marry a Mason, transformed himself into a crocodile, and, despite the masquerade, played the piano wonderfully well.
“One day when lecturing at Lille, I told my audience that I had just had an apparition of Nautilus, the most daring affront on human credulity I had so far risked. But my hearers never turned a hair. ‘Hear ye, the doctor has seen Nautilus,’ they said with admiring glances. Of course no one had a clear idea of who Nautilus was I didn’t myself but they assumed that he was a devil. Ah, the jolly evenings I spent with my fellow authors hatching out new plots, new, unheard of perversions of truth and logic, each trying to outdo the other in organized mystification. I thought I would kill myself laughing at some of the things proposed, but everything went; there is no limit to human stupidity.”