Question: What Shakespearean play named after a King of the Britons recorded by the medieval scribe Geoffrey of Monmouth included a character  considered a villain, obsessed with power and overthrowing her elderly father?
Sentence (from "Regan (King Lear)"): Regan is a fictional character in William Shakespeare's tragic play, "King Lear", named after a King of the Britons recorded by the medieval scribe Geoffrey of Monmouth.
Relevant evidence: Yes