A POWERFUL MAN
Once upon a time there was a king who was colorblind ... he could not distinguish red from green. But the problem was, he did not know that himself. One day there was a new law that stated that there was no difference between red and green, so there shouldn't be more than two different words for it. Of course the people ignored it. Red was red and green was green; everyone saw the difference so they refused to pretend there was no red or no green. The king roared with anger when he heard that . So he issued a law: anyone who now claimed that red was not the same as green, was thrown into prison without trial.
Of course that didn't work either. The truth was the truth and the people knew that the king was wrong. Sometimes someone had the courage to tell the king about his mistake, but no one ever heard from them again. In a cell below the royal palace prisoners usually didn't live long. Most died within one month from malnutrition, and of not, some contagious disease did the job. How many people ended up in jail through history... nobody knew. But something like this couldn't last forever, of course.
A doctor succeeded in producing two pensils which were exactly as bright but one was red and the other was green. He could see the difference but the king couldn't. Then the king was challenged to draw as many crisscrossed lines as he could on a piece of paper with the green pencil. After that he was told to use the red pencil, drawing lines representing a clear figure or letter. The doctor saw what the king had drawn and there was the evidence: the king was colorblind.
Needless to say, the law about red and green was abolished.
Many years passed. But then suddenly .... One day little Nick came home after school and said that they had talked about colorblindness at school. Grandpa said that the former king was colorblind. Colorblind??? The boy didn't believe a word of that. Grandpa began to wonder if Nick ever attended history lessons at school ... or would he be so bad at history? Grandpa decided to find it on the internet so that he could show it to his grandson! But search after search resulted in less than nothing. Less than nothing? Yes, because he found no documents indicating that the king had the habit of throwing people in jail when they claimed that red and green were not the same. Instead he found several websites with the topic "how did the red / green myth arise?"
Myth??? Grandpa knew what he knew, and that was not what those websites wanted him to believe! It was clear: the king, powerful as he was, could easily make sure that there was no tangible evidence of the blunder he had ever made. The truth had been carefully erased ...
PS. Did I mention that nowadays more and more websites show the "evidence" that the church has never maintained that the earth was flat?