Siege of Florence (1529–1530)

The siege of Florence took place from 24 October 1529 to 10 August 1530, at the end of the War of the League of Cognac. At the Congress of Bologna, the Medici Pope Clement VII and Emperor Charles V agreed to restore the Medici family in Florence. A large Imperial and Spanish army under Philibert of Châlon, Prince of Orange and Pier Maria III de' Rossi surrounded the city and after a siege of nearly ten months, captured it. They overthrew the Republic of Florence and installed Alessandro de' Medici as the ruler of the city.

The Florentines had thrown off Medici rule and established a republic after the Sack of Rome in 1527; the Florentine Republic had continued to participate in the war on the side of the French. The French defeats at Naples in 1528 and Landriano in 1529, however, led to Francis I of France concluding the Treaty of Cambrai with the Holy Roman Emperor Charles V. When Pope Clement VII and the Republic of Venice also concluded treaties with the Emperor, Florence was left to fight alone. Charles, attempting to gain Clement's favor, ordered his armies to seize Florence and return the Medici to power.

The Republic resisted this incursion; but, left without allies and betrayed by many of the mercenaries in her employ, Florence was unable to keep fighting indefinitely. After the capture of Volterra by the Imperial forces and the death of Francesco Ferruccio at the Battle of Gavinana, further resistance became impractical, and the city surrendered in August 1530.