9. Roanoke Colony
What I'm proposing here is not so much a historical figure, as it is a group of historical figures in one of the world's greatest mysteries. Back in the 1600s, England sent a group of settlers to what would become Virginia in the hopes of creating a new colony. They set up shop on Roanoke Island, but things weren't going what you might call swimmingly, so one of the leaders went back to England for more supplies. When he returned a number of years later, the settlement was gone. There were no traces of human life, and the entire village had been torn down. All that was left was the word, "Croatoan" carved into the bark of a tree. So where did the settlers go? If that doesn't sound like the set-up for a good Doctor Who episode, I don't know what does. The Doctor and his companion could arrive at the colony shortly before it disappears, and of course the Doctor's natural curiosity would make him want to stick around to finally figure out the mystery of Roanoke Colony. Maybe there could be a return of the Judoon, where there was secretly an alien hiding out amongst the humans, and they destroyed the colony for harboring fugitives. I don't know, there's limitless possibilities here!