It’s 1459, and Cosimo de’ Medici has been the unofficial master of the Florentine republic for twenty-five years, a wily politician whose authority is underpinned by money and patronage.

The money comes from banking. Cosimo’s father, Giovanni di Bicci, built up the Medici bank, securing the lucrative papal account in Rome, but Cosimo turned it into a European powerhouse, with branches in Venice, Geneva, Avignon, Bruges, London, Milan and Pisa. In the process he turned himself into one of the richest men in Christendom.

Wealth gave Cosimo his edge over the other “big men” or oligarchs of the republic. Cosimo’s loans became indispensable to the government. His web of allies and clients, his amici, based in the family’s stronghold of San Lorenzo but spanning the city, was beyond the reach of other patrons. This network of partisans enabled Cosimo to outmanoeuvre the Albizzi faction in the 1430s – and, once in power, he exiled his main rivals and rigged the republic’s electoral system so that only Medici friends ended up in city hall.

Cosimo converted his fortune not only into political but cultural capital, and the two were intricately linked. He has cultivated Florence’s vibrant world of humanistic learning and artistic innovation, closely associating himself with a movement later to be labelled the Renaissance. From the Dominican convent of San Marco to the recently completed Medici palace, Cosimo’s magnificent urban projects carry the signature of architects, painters and sculptors such as Brunelleschi and Michelozzo, Fra’ Angelico and Benozzo Gozzoli, and Donatello.

Now aged 70, Cosimo will be dead in five years, but his long rule has laid the groundwork for the succession of his son Piero and grandson Lorenzo the Magnificent. Yet his pride is matched by fears for his legacy and, like all Florentines, for his immortal soul. There’s been a backlash against Cosimo’s electoral controls, cracks within the ruling group, and a year before we meet him, in 1458, he staged a minor coup, ruthlessly suppressing dissent and tightening his grip on the republic. He’s also aligned Florence with the new duke of Milan, Francesco Sforza, whom he bankrolled and whose loyalty is to the Medici rather than to the republic. During the 1458 coup, Sforza troops were waiting in the wings, as they would be again during a failed bid to oust Piero in 1466. Cosimo says he cares deeply for the honour of the city, as well as the house of the Medici, but he knows that many of his fellow citizens see him as that most Florentine of bogeymen, a tyrant.

Cosimo wants to convince you, and perhaps himself, that his magnificent civic and religious patronage have offset his sins against the republic. He also needs to think that his good works have wiped out his sins in God’s ledger, especially the usury that has made him so rich, and earned him enough spiritual credit for eternal salvation. Reflecting the mercantile culture of his city, Cosimo weighs up profit against loss, and wants to believe he has balanced the books.

David Rosenthal


To cite this essay, we suggest:
David Rosenthal, ‘Introduction: Balancing the books’ published online 2019, in ‘Hidden Florence’, The University of Exeter,

Further reading:

Dale Kent, Cosimo de’ Medici and the Florentine Renaissance (New Haven: Yale University Press, 2000)

John Najemy, A History of Florence 1200-1575 (Malden: Blackwell Publishing, 2006)

Frances Ames-Lewis, ed., Cosimo ‘il Vecchio’ de’ Medici, 1389-1464 (Oxford: Clarendon Press, 1992)

You can read Cosimo’s personal diary (ricordi) on the events leading up to his takeover of Florence in 1434 in Giovanni Ciappelli, Memory Family and Self, trans. Susan Amanda George (Leiden: Brill, 2014). The best-known fifteenth-century biography of Cosimo is by the bookseller Vespasiano da Bisticci. Vespasiano da Bisticci, The Vespasiano Memoirs: Lives of Illustrious Men of the XVth Century, trans. WG and E Waters (Toronto: University of Toronto Press with the Renaissance Society of America, 1997)