Childeric

Childeric was the son of Pepin VI and Berengaria. As was tradition the king has two sons, one good and one bad. Childeric was bad. He was destined to attempt to usurp the throne of his brother, Pepin VII. After the death of Pepin VI, his brother was to be king. At Pepin's coronation, Childeric attempted to announce himself a god after Pepin decreed he wasn't. The Doctor and Frobisher landed amidst the service. Initially they were seen as godly ambassadors, but they revealed they weren't. With that Childeric ordered their death. However, Eugene Tacitus saved them by saying all previous kings experience mental tiredness after coronation. (BFA: The Holy Terror)