What's In a Name...?

Ok... no music tonight, but a perplexing question....

I happened to have my attention snagged by a documentary on PBS titled "African American Lives 2," hosted by Henry Louis Gates, Jr. He basically tracked the historical lineage of several notable blacks, including radio personality Tom Joyner, whose lineage is the inspiration of my question.
The question that arises in my mind is that if so many blacks were undereducated or uneducated during the times preceding my birth, how is it that some ended up with Greek and other names?
Tom Joyner's father was named Hercules. My own father's name is Ulysses. In the call center where I work, one man who called in was named Leonidas.
How did this come about? What would inspire these folks to give their children these names?
Anyone out there with a family member with a name as such, please give some feedback in the form of a comment. If you know the history behind that name, teach me something new.

And I just learned something new... the Chicasaw nation, as well as the Cherokees... Native Americans, owned black slaves.
And this is why one should write their paradigms in pencil.