It's not a coincidence that most of the "Irish slaves" depicted in these memes aren't actually Irish. It's also not a coincidence that you mostly see "I'm not racist, but" people sharing them. Irish historian Liam Hogan tracked down this myth to a 1990s book by Holocaust denier Michael A. Hoffman II, which was a big hit in white supremacist circles. In 2000, the myth was given more credibility by a book called To Hell Or Barbados, written by a non-historian who unfortunately wasn't too clear on the definition of "slavery." He also claimed, with zero evidence, that the Irish were branded like cattle, and that Irish women were sold to "stud farms" for breeding purposes, among other exciting details. Anyway, we're sure this clarification will make the people who shared these memes with no ulterior racist motives stop at once!

Related: 6 Things We Only Believe Today Because Of Propaganda

Now, the myth of the flat Earth may not have spread a whole lot back in the day ... but the myth of the myth of the flat Earth did, and for a very specific reason. When that aforementioned novel about Columbus came out in 1828, some anticlerical scholars smelled an opportunity to show how hostile the Catholic Church was to scientific thinking. French author Antoine-Jean Letronne published an article titled "On The Cosmological Opinions Of The Church Fathers," which basically argued that Catholic priests and the pope had the big dumb, citing the fake Columbus story as evidence. Each new book about Columbus drew from the previous one and expanded on the generalized stupidity of his contemporaries, until they made it look like he was the only person in Spain who didn't think the Earth was a pancake.

Meanwhile, an English scholar named William Whewell gave the myth even more credence by taking three obscure flat Earth believers from history and making it look like theirs was a common belief in the "Dark Ages." It's like when the media pretends two teenagers eating deodorant on YouTube is a new fad. Of course, there's always the possibility that a lot of people did share this belief back then, but we just didn't know it because Facebook didn't exist yet.

Related: 6 Insane Examples Of Modern Propaganda By Major Countries

When South Carolina became the first state to try to ditch the Union in 1860, they released a document listing their causes. Not only is it all about slavery, but they also bitched about Northern states being allowed to pass laws that endangered such a noble institution. How dare they decided that they wanted to treat fugitive or transported slaves like people! Other states, like Texas, shared those complaints. Southerners used the "states' rights" card when they didn't like a law, but when it came to defending slavery, they were big fans of having a centralized government telling everyone what to do. It was less about independence and more about "How do we keep this gravy train powered by centuries of human suffering going?"

But by the time the first Confederate statues started popping up in the late 19th century, they couldn't put "To my white supremacist grandpa who died for no good reason" on them. So they went with stuff like "To all the heroes of the South who fought for the principle of States' Rights."

Brian Reading / Wikimedia CommonsThey also turned gramps into a totally ripped angel with a massive ... sword.

Former Confederates who were still alive gave more weight to the argument by going, "Uh yeah, that's the ticket." In 1894, General Joseph Wheeler gave a speech arguing that the North violated the Constitution, cessation was a right, and the South in fact opposed slavery. They were only fighting to protect their rights! Good thing humanity has evolved, and this stubborn refusal to acknowledge and learn from your political mistakes could never happen these days.

Related: 6 Brainwashing Techniques They're Using On You Right Now

So where did the idea of the Inquisition as a cavalcade of horror come from? England, which had a vested interest in portraying Spain as a bunch of backwards savages, thus making themselves look more civilized in comparison. It also served their colonial interests. Spain ruled more colonies than anyone else, and England was already late to the "enslave natives and steal their land" party. Portraying the Inquisition and by extension Spain as evil overlords to the pagans of the "new" world helped paint England as more enlightened. The English wanted you to believe it was all Thanksgiving and hand-holding in their colonies, while Spanish America was full of forced conversions and human bonfires.

The myth lasted a long time, not only in the public imagination but among historians as well. All the way up until the 1960s, historians upheld the Black Legend of the Spanish Inquisition as the Black Truth. It was only after scholars began to question the underlying assumptions of the field that they bothered to reevaluate the evidence. Now we know they were less omnipresent Hitlers and more like the DMV with slightly more torture.

Related: Memes You Probably Helped Spread Are Secretly Propaganda

Of course, such fuckery predates the internet and goes back to the very beginning. Initially and expectedly, former Nazis denied the Holocaust, which was even less convincing when you had all those corpses right there. What's surprising is that they quickly attracted academic support from well-respected sources. Friedrich Meinecke, an eminent German historian and one of the founders of the Free University of Berlin, wrote The German Catastrophe in 1950. It was a defense of the Nazis' actions which, in classic German fashion, both mitigated Jewish suffering and blamed them for it. Despite the fact that Meinecke was openly antisemitic, some people read his book and said, "Hmm, yeah, checks out."

Wikimedia Commons"Yes, this looks like a respectable person and not at all like a cartoon supervillain."

Meanwhile, French National Assembly member Paul Rassinier denounced reports of gas chambers, on the basis that he was in Buchenwald in 1943 and never saw any. Never mind that Buchenwald was not an extermination camp. He wrote a bunch of books on the matter, culminating in his masterpiece, The Drama Of European Jewry, in which he argued that the Holocaust was an inside job. As in "Zionists" faked it in a grand Ocean's Eleven-type heist to scam money out of Germany. Did we mention he was an antisemite too?

Then there was American historian Harry Elmer Barnes, who taught at Ivy League institutions. Unfortunately, he was also pen pals with Rassinier and translated his books for publication in America, where they remain fan favorites among frothing racists. What's most infuriating is that since he and the others were considered serious academics, it led to legitimate outlets like The Los Angeles Times publishing straight up Holocaust denial. And they couldn't even blame it on the internet making people dumber back then! So let's count our blessings here.

For more, check out 10 Weirdly Conservative Hidden Messages In 'Con Air' - Today's Topic:

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