The Dark Ages?

Ignorant, unwashed savage.

Most of what we think we know about the Middle Ages is wrong. This is especially significant to Catholics, because many of the misconceptions were deliberately promoted as anti-Catholic propaganda. The idea is that our ancestors lived in darkness and heathen ignorance, under priestly oppression, until the Reformation turned on some sort of light.

This is utter bollocks. In a lot of ways, the Medieval period was more civilized than the Renaissance that followed. No slavery, for example; no trials for witchcraft.

Here's a quick summary of some of the more egregious lies your teachers told you:

http://listverse.com/2009/01/07/top-10-myths-about-the-middle-ages/