King Stewart III was the King of England as seen in "Peter's Progress".
When he becomes enamored of Lady Redbush, only to find she is already engaged to Griffin Peterson, he has Peterson exiled to America to the new colony of Quahog and reports he has been killed. He soon marries Lady Redbush himself but they put off consummating their relationship. King Stewart asked about having sex with Lady Redbush several times but they find excuses and complains about how busy they are. Later, King Stewart's court jester informs Redbush that Peterson is still alive. She escapes from King Stewart to sail to Quahog.
When King Stewart belatedly discovers she is missing, he invades the colony to force her return. Challenged to a talent contest for the hand of Redbush by Peterson, King Stewart's act consists of a routine he "borrowed" from his jester. Griffin Peterson and his friends soundly defeat him with a performance of the song, "Nerds!".