Where most slaves came from?

Slavery has occurred for a long time throughout history, and all sorts of groups have been enslaved. The majority of slaves don't necessarily originate from any single location. But the term slave did come from Vikings capturing and selling of Slavic peoples back around the 500's, (notice that slavery did occur prior to that). Since that time, slavery has occurred all over the globe within all sorts of cultures, so a geographical location from which slaves most come from doesn't exist. If you want to be fancy about it... most slaves come from "oppression".