Impoverished noblemen were always a problem in Venice. By law, once a patrician family was inscribed in the Libro d'Oro, it could not lose its seats in the Maggior Consiglio.
During the decline of the Republic, down-at-heels patricians flocked to the cheap housing in the parish of San Barnaba. The hotter bloods among these 'Barnabotti' were always ready to stir things up against the government and to sell their votes to the highest bidder. The more radical Barnabotti kept the Council of Ten’s spies on their toes. Other reduced noblemen in the district, resigned to their lot, made do on the meagre stipend supplied by the State (on the condition that they didn’t follow any trade, or marry and make any more little Barnabotti).
During the 17th century the numbers of poor nobles in Venice grew alarmingly, especially after the fall of Crete. Meanwhile, the nobility itself was in crisis. The great plague of 1630 decimated its numbers, leading to the decision to inscribe a new band of wealthy Venetians into the rolls, those who were able to fork out 100,000 ducats for the privilege. Still their numbers declined, as some families died off and the financial burdens of state service ruined others. Many became new Barnabotti.
Image by Didier Descouens, Creative Commons License