Hamlet's father
From Tardis Wiki, the free Doctor Who reference
Hamlet's father was a character in William Shakespeare's play Hamlet.
Shakespeare was inspired by the Tenth Doctor and Martha Jones to write about father-son relationships when they encountered him in 1599. (TV: The Shakespeare Code)
In his first thoughts for the early scenes of Hamlet, Shakespeare wrote that Hamlet was the son of a dead king. He was murdered by his brother who then married his wife to steal the throne. In the first draft, Hamlet discovered this from a magician as such things were "common in the theatre". This character was replaced by the ghost of Hamlet's father in the final draft. (PROSE: Notes on a Play)
