Wanchese

 was an native American, a member of the Algonquian, who asked the Sixth Doctor and Professor George Litefoot to cure his daughter of an illness, they could not as he wouldn't allow them to enter the TARDIS to get oxygen and anti-biotics, so he tried to execute them, but were stopped by John White. He talked about the Children of Croatoan. He later became the servant of Sir Walter Raleigh, and on the Doctors orders he negated the timeline that created the Children. (AUDIO: Voyage to the New World)