I keep coming across a particular kind of ignorance lately.
It can be summed up as "Before slavery, everyone in Europe was white."
There are two problems with this statement:
1. We don't know the origins of slavery, but what we do know is that humans have been claiming ownership over other humans for a very long time. Many Americans, however, use the term "slavery" solely to mean southern chattel slavery - a very specific thing. Southern chattel slavery was skin color based (skin color based oppression exists all over the place, but to my knowledge this is the only period in history where skin color marked a person as a slave) and had many aspects of serfdom as well as cash slavery. But it is not the only kind of slavery that exists - present tense, because there are an estimated 30 million slaves alive today.
2. Everyone in Europe being white is simply not true. Most scholars believe that the Huns were an Asiatic race, and the Monguls, who made it far enough into Europe to produce offspring, certainly count. During the Roman period, enough black people made it to Europe to produce a noticeable uptick in the amount of African DNA in the European genome - yes, we can track those markers and we can make a decent estimate as to when they entered a population. (These blacks were probably a mix of slaves, traders, and voluntary migrants, and the markers show up all over Europe).
3. Latest research (subject to change as latest research always is) indicates that the white skin mutation itself is only five to seven thousand years old. So, go back before "anyone else" was in Europe...and, uh, yeah, everyone was black. (Neanderthals do appear to have been white and with the interbreeding there may have been some fairly light-skinned people around, but this would have been noticeable).
So, please, people, stop telling me there were no people of color in pre-Renaissance Europe. I'm starting to get snarly about it.