Have you ever wondered why February only has 28 days except for leap years (Schaltjahr)? Don’t lie now, tell the truth, the whole truth and nothing but the truth. (Die Wahrheit, die reine Wahrheit & nichts als die Wahrheit) Yes, me to?!
To quench (stillen) my own thirst for knowledge (Wissensdurst), I jumped straight onto YouTube and typed in that very question. To my surprise, there were quite a number on the topic. I plumped for (sich für etw entscheiden) the one below because the name of the channel (It’s ok to be smart) tickled my fancy (jdm gefallen).
Of course, you are completely right to imagine it has something to do with history! And unfortunately, it’s not as simple as if some pissed monk misread some ancient writings from a distant age, then gave the King/Queen of the time FAKE News, S/he decreed it (etw verfügen) and it has stuck ever since.
So put the kettle on (das Teewasser), get yourself a cup of tea, make yourself comfortable, pens & paper at the ready (the latter only if you are really keen) and enjoy the short film.