Eric Schumacher posted a picture online of a science textbook being used by his child. The student was supposed to be learning about the making and history of silk. This is the quote about how silk became accessible to those who were not wealthy and powerful,
About 2,500 years ago, however, Christian monks snuck silk moths out of the country in their hollow walking sticks, and the secret of silk making was revealed to the rest of the world.
If you are doing the math, this is currently A.D. 2014. That would place these Christian monks at close to 400 years before Christ.
So this textbook gets an F in history and an F in math. Makes you wonder about its scientific accuracy.