The Headman was the leader of an English village which came under the control of a group of Terileptils in 1666.
He and the poacher halted a villager from executing the Fifth Doctor and Richard Mace as plague carriers at the Terileptil's orders. He then ordered them locked in a room at the Miller's barn.
The Terileptil leader ordered the headman to take the Doctor to the Squire's manor. When he and the poacher entered the room, the Doctor removed the headman's control bracelet and pushed the headman back out into the barn while Mace held the poacher. The headman regained control of his brain, and told a villager that there was a voice in his head telling him what to do. The villagers then thought the Doctor and Mace were not just plague carriers, but warlocks too. The villagers began to make a fire to burn them, but the Teriletpil Android, dressed as the Grim Reaper, broke into the barn, scaring the headman and the other villagers off. (TV: The Visitation)