Stephano and Trinculo

A "clown double-act" featured in William Shakespeare's play The Tempest.

First thoughts
A need for "clown business" was one of Shakespeare's first thoughts in his earliest working notes for the play. He considered a funny sailor, a shoemaker, a soldier, a funny butler, someone who was working for the Duke who was later named Antonio, a tailor, and a cook as possibilities. Out of these, he questioned why a shoemaker would be at sea and underlined tailor. Shakespeare then explored the idea of a potential double-act, further listing two funny butlers, a priest and the Duke's Jester, and subsequently crossing out priest.

Later, having evidently settled that the comedy double-act would indeed be a double-act, Shakespeare wrote that the duo could get drunk on wine from the shipwreck which had stranded them and several others on the exiled Duke of Milan Prospero's island. He also planned for them to appear in a "funny dressing-up scene", commenting that enormous trousers were "always hilarious". (PROSE: The Tempest – A Work in Progress)

Following Forbidden Planet
At some point, the Tenth Doctor became aware Shakespeare was struggling to write his play. He sent him a battery-powered Blu-ray player and a copy of Forbidden Planet to draw inspiration from, reasoning that it was "not stealing" because the film was based upon the version of The Tempest Shakespeare was about to write.

Imbued with new thoughts, Shakespeare, having decided that Prospero was not just a Duke but also a wizard who studied books of magic, removed the coincidence of Prospero and Antonio ending up on the same island, with Prospero causing a storm using his magic staff which forcefully brought the ship there. The magic shipwreck also served to explain why only Antonio, the King of Naples, the Duke's son, the courtiers and the funny servants came to shore. The boat was located on the other side of the island, with the rest of its crew as its occupants all asleep inside.

Shakespeare was also inspired to add a fairy or familiar spirit named Ariel into the play, with this new character leading the clowns into a swamp at one point, though Shakespeare initially wrote (and later crossed out) that Ariel would shove the clowns into a river. As Ariel was invisible, albeit not to the audience, the playwright also opted to do the "people-being-pinched-by-invisible-attacker gag", noting it had been "ages" since he wrote the same thing into A Midsummer Night's Dream and banking on nobody remembering it. While in the process of devising a "baddie" for the piece, Shakespeare made the decision to pair up a primitive which he dubbed "Canibal" with the clowns.

Coming to the play's conclusion, Shakespeare outlined that all three different plot lines (including the comedy business with the clowns and Canibal) would be "sorted out" by Prospero and Ariel. He wavered over whether this was "too easy" and if he could claim it was a deliberate Deus ex machina to impress Johnson. Brushing aside these concerns, he stated in his notes his belief that he was "nearly there" and that the rest of the story would "write itself", with thinking of names for the clowns and other characters the only thing left for him to do. (PROSE: The Tempest – A Work in Progress)

Behind the scenes
Although The Tempest – A Work in Progress does not identify The Tempest's clowns by name, they are clearly recognisable as Stephano and Trinculo. Stephano was a butler while Trinculo was a jester, two of the many possible professions for the clowns considered by Shakespeare early in the story.