The real Marquis of Grillo lived in the early 18th century, but, for this take-off on the marquis' life, director Mario Monicelli, has changed the time period to the early 19th century when a lot more was going on in Rome.
The marquis (Alberto Sordi) amuses himself by throwing red-hot coins to beggars, occasionally walling up the store entrance of an offending merchant and installing a urinal there instead, and generally making witty and broad comments on the life going on around him.
His existence suddenly gets a lot more interesting when he discovers his physical (unrelated) twin in a Roman tavern (also Alberto Sordi) a drunkard who works transporting coal when he is sober.
As a joke, the marquis takes the passed-out drunk to his mansion and puts him in his bed, fully intent on convincing the drunk and everyone else that this man is the real marquis.

Cast:
Alberto Sordi, Caroline Berg, Andrea Bevilacqua, Tommaso Bianco, Riccardo Billi, Flavio Bucci, Angela Campanella

Director:
Mario Monicelli