Here’s a very old conspiracy theory for you: the spurious accusations against the Knights Templars. As you can see from this late-15th century depiction, the charges were successful and many of the leaders were burned as a result.
So if you don’t know, the Knights Templar was a religious order started to help protect Christians seeking passage to the Holy Lands around Jerusalem during the Crusades. What made them distinct is that in addition to the usual oaths monks avowed, these guys were expert soldiers, known for their skill in battle. As they grew more successful, they were known for other things: diplomacy – because they grew savvy about how power arrangements in the Middle East operated – and banking- because they managed to accrue a lot of wealth (supposedly held in corporation so they weren’t violating their oaths).
One person who owed the Knights Templars a heap of money was King Philip IV. The Knights had lent the monarch the funds for his sister’s dowry and fighting with his neighbors. But n 1307 Philip was broke, and he had long had a habit of taking other groups’ possessions when he needed them (most infamously, from his Jewish subjects in 1306). So, the king ordered the Knight Templar leader, called the Grand Master Jacques de Molay, arrested, and formally accused the order of heresy.
These accusations were shameful indeed for Medieval Christians. I will quote some of them, which claimed that the Templars “when professing, the brothers [ie, the Templars] were required to deny Christ, to spit on the cross, and to place three ‘obscene kisses’ on the lower spine, the navel and the mouth; they were obliged to indulge in carnal relations with other members of the order, if requested; and finally they wore a small belt which had been consecrated by touching a strange idol, which looked like a human head with a long beard. . . . “.
There was no evidence that any of this ever actually happened, except that produced by torture of some of the captured Templars. Arrested on Friday the 13th of October 1307, many were burned in 1310. The Order was officially suppressed two years later, and Jacques de Molay, the Grand Master, burned in 1314.
Source(s): Quote from Wikipedia, Barbara Drake, “The Chinon part Papal absolution to the LAST templar, Master Jacques de Molay,’ _The Journal of Medieval History_02, Vol 30, issue 2 (2004), pp 115-116 116 n. 34: stating an example of the original decree survives in Paris, _Archives Nationals_, J 413, n 23; and also citing G. Lizerand, _Le dossier de l’affaire des Templiers_ (Paris, 1989). Image, BL, Royal 14 E V, f. 492v. Giovanni Biccaccii, Laurent de Premierfait, Des Cas des nobles hommes et femmes (ms ca. 1479-1480).