It was also a "fact", in the times of Galileo, that Earth is in the center of the universe and the Sun rotates around it. But that might be too ancient, so how

It was also a "fact", in the times of Galileo, that Earth is in the center of the universe and the Sun rotates around it. But that might be too ancient, so how about another: before the 80's there was "scientific consensus" that ulcers are caused by all sorts of things other than bacteria. Dude who discovered they were, in fact, caused by bacteria, was nearly kicked out of his field. History is rife with "facts" that weren't actually, you know, real facts at the time, even though there was "scientific consensus". Note that I'm not an anti-vaxxer, and I'm not a climate change denier. I also don't imbue "scientific consensus" with magical properties, seeing how often it was dead wrong.