In Rome skullcap of 1809 the marquis Onofrio del Grillo, Roman noble to the court of Pope Pius VII, she spends her days in complete idleness, frequenting taverns and taverns, cultivating clandestine love affairs with commoners and holding a rebellious attitude in the eyes of her mother and conservative, bigoted and authoritarian kinship.

His main pastime, which makes him famous throughout the city, is made up of innumerable jokes and mockery of which his aristocratic family, made up of extravagant characters and closed to the outside world, is often the victim.

The rich noble landowner is always able to come out with humor and in a daring way from the many and unthinkable situations throughout the comedy, shamelessly exploiting even the knowledge of the often complacent upper middle class (an example is the court scene with the sentence to pillory by the Jewish cabinetmaker Aronne Piperno).

The Marquis then meets a young and beautiful actress named Olimpia and she makes him seriously think he can leave Rome to go to Paris.

A chance encounter with a poor man carbonaio alcoholic, Gasperino, his perfect double, inspires the nobleman to crown his burlesque repertoire. In various situations he comes to involve the Pontiff in the name of a justice and renewal always invoked but which never seriously manage to worry the bold and brilliant "Sor Marchese": in the end, in fact, after a false sentence to the guillotine inflicted on him by Pius VII, is pardoned by the latter, who allows him to resume his place among the Papal Chairmen.

The Marquis del Grillo, between truth and legend

In the Church of San Giovanni dei Fiorentini, the first chapel on the right, the real Marquis Onofrio del Grillo has been buried since 1787.

There are many anecdotes about the Marquis and many of the jokes reported in the film are similar to those handed down, between legend and truth, in Roman history.

Buontempone, he wanted the motto engraved on his coat of arms:
"Er cricket of the marquis always zompa, and who zompa ... cheerfully always lives" 
guaranteeing immortality with it.“