Holy Roman Emperor
From Tardis Wiki, the free Doctor Who reference
The Holy Roman Emperor was the ruler of the Holy Roman Empire.
In 800, Pope Leo III crowned Charlemagne as emperor. (PROSE: The Lonely Computer)
Maximilian I was the Holy Roman Emperor in 1504. (AUDIO: The Ghosts of N-Space)
In an alternate timeline in which all of history occurred at once, Winston Churchill was the Holy Roman Emperor. (TV: The Wedding of River Song)