TIFU by telling my future Mother-in-Law that Joan of Arc might have been schizophrenic

This was, of course, not today... but instead about 35 years ago. My girlfriend had a French mother and was from Orleans, France. I didn't know all that much about French history at the time; so if I read something about French history somewhere I'd bring it up to see what my girlfriend's mom thought.

So one day I read an article somewhere--maybe Psychology Today?--that analyzed the curious case of Joan of Arc, the teenage girl who help lead an army in France after hearing God speak to her, before being burned at the stake and becoming a martyr. The gist of the article was that using modern psychiatric interpretations, her behavior and her story indicated that she was likely schizophrenic and the "voice" of God that told her to become a warrior was essentially like many of the internal voices that plague folks suffering from schizophrenia.

So I brought it up to my future Mother-in-Law. I mentioned "You know Joan of Arc, right? Well doctors now understand that she was probably suffering from schizophrenia, and the "Voice of God" was just her internal schizophrenic voice instructing her. Not unlike how the "Son of Sam" killer had a dog talking to him and tell him what do it. So really she was just suffering from a mental illness."

This tiny, sweet, calm and humane woman that I loved like a second mother, instantly widened her eyes to almost double in size, and slapped me hard across my cheek. And then she stood there shaking, while pointing a finger at me and not saying a god damned word. Then she wandered away.

I was absolutely dumbfounded... and I asked my girlfriend and she tells me "don't worry about it. She just likes Joan of Arc."

Seemed like an over-aggressive response to me, but whatever.

So about three years later we were on our European honeymoon and we stayed with her Grandma in Orleans for a few weeks. And everytime we'd wander around the city I'd see signs, and statues, and paintings, and churches, all with Joan of Arc's name on them. I was starting to realized that she was a MUCH bigger deal in this town my mother in law grew up in than I ever imagined. She was "the Maid of Orleans" I found out. Then my wife's Grandma pulled out some scrapbooks of my wife's mom when she was younger. And it was like pulling out your obsessed daughter's scrapbook full of hundreds of Taylor Swift pictures and ephemera; except it was all Joan of Arc related instead. And there was a bunch of stuff about her literal and concrete plans to become a nun when she was a teenager, inspired by her hero with a direct line to God, Joan of Arc.

Whom, you might recall, I claimed was actually schizophrenic.

I have no idea why my wife didn't better prep me for all of this; sometimes she'd just let me shoot myself in the foot because she found it god damned hilarious.

TL;DR I told my future mother-in-law that her personal hero, the saint Joan of Arc, hero of France with a direct line to God, who inspired her to almost become a nun... I told her that scientists now believe she was schizophrenic.