The term “black people” [черные люди] had widespread recorded usage in Russian between 12th and 17th centuries.
Initially, it meant “people of the lowest classes who weren’t exempt from any taxes.” There are different explanations for why they were called “black.” One explanation was that they cultivated land and the most fertile lands in Russian are referred to as “black earth” [чернозем]. Other version is that their faces were black with soot.
By the 18th century, the term was shortened to “blacks” [чернь] and was used to refer to the lowest social classes. Catherine the Great, for instance, kept ranting against the folks who thought it made sense to teach “blacks” to read and write.
Traces of this usage remain in Russian today. The term for somebody who does unqualified manual labor is “a black worker” [чернорабочий].
The distinction between “black bone” (people who do manual labor) and “white bone” (those who don’t) also still exists.
By the 1960s, a racialized usage of “blacks” was in use to refer to the slightly more swarthy inhabitants of the Transcaucasus region. All of the racial stereotypes about the “oversexed, lazy, dishonest, thuggish blacks” were attributed to them. Unlike the original usage that had no racial content, this is already a recognizably racialized one.