Claudius

Claudius served as the Emperor of the Roman Empire during the 1st century. He had a distinctive stutter, which got worse when he was nervous. During his reign, he visited Britain for nineteen days. After this, a demon impersonated him, claiming to have escaped the empire and joined a Celtic nation as a form of retirement. This was actually a trap for the Fourth Doctor. (AG: The Relics of Time)

Behind the scenes
Both Derek Jacobi and David Warner have portrayed Claudius in adaptations of I, Claudius.