In This Article Expand or collapse the "in this article" section Cosimo I de’ Medici

  • Introduction
  • General Overviews
  • Biographical Treatments
  • Document Collections and Bibliographies
  • Economy
  • Eleonora di Toledo
  • Letters, Learning, and Cosimo
  • Military
  • Political Culture and Politics
  • Public Displays and Festivities
  • Reformation and Religion
  • Science and Alchemy
  • Universities

Renaissance and Reformation Cosimo I de’ Medici
Ann E. Moyer
  • LAST MODIFIED: 26 October 2023
  • DOI: 10.1093/obo/9780195399301-0523


Cosimo de’ Medici (b.1519–d. 1574), son of the condottiere Giovanni delle Bande Nere (Ludovico de’ Medici [b. 1498–d. 1526]) and Maria Salviati (b. 1499–d. 1543), grew up without expectation of assuming political leadership. Upon the assassination of the first duke of Florence, Alessandro de’ Medici (r. 1530–1537), Cosimo, then aged seventeen, was identified as next in the line of succession and put in place as head (capo) of the city by a committee representing mainly papal and imperial interests. Cosimo survived a nearly immediate revolt led by exiles (fuorusciti), whom he defeated at the Battle of Montemurlo (August 1537), winning recognition as duke from Charles V. Cosimo continued to balance papal and imperial politics to build a virtually independent state. The conquest of Siena and its territories was complete by 1559, ending both the Italian wars and French influence in Italy. He acquired the papal title Grand Duke of Tuscany in 1569. In 1539, Cosimo married Eleonora of Toledo (b. 1522–d. 1562), daughter of the Spanish viceroy of Naples; together they had eleven children. Alessandro’s widow had retained ownership of the Palazzo Medici; thus, in 1540 they moved into the refurbished apartments at the Palazzo Vecchio that had been used by the priors. In 1549 Eleonora’s dowry money purchased the Palazzo Pitti; it too required extensive renovations, still incomplete when Eleonora, already weakened by tuberculosis, died of malaria with sons Giovanni and Garzia. Cosimo handed over his duties officially to his son Francesco in 1564, although he still retained authority in a range of matters; in his last years he was incapacitated by illness. Scholarly assessments of Cosimo’s career have changed significantly over time. Older interpretations that had valorized Florence’s earlier republican governments often cast the city’s transition to the Medicean state in terms of moral failure, and the Medici rulers themselves as simply absolutists. More recent scholarship has shed new light on the nature of those earlier “republican” governments and also to a fuller understanding of the Medicean state as it developed in a European and Mediterranean context. These studies have revealed the continuities of administrative control among elite families throughout the century, tempering notions of absolutist rule in favor of the “mixed constitution” favored by many contemporaries. They have examined Cosimo’s infrastructure projects across Tuscany; the nature of economic planning; his role in promoting universities and education; and, of course, Cosimo’s interest in the city’s continuing excellence in the visual arts, letters, and scholarship.

General Overviews

Understanding Cosimo and his life requires a broad understanding of Florentine history before Cosimo’s period of rule. A good introduction to the literature is Strocchia 2015. Najemy 2006 provides an overarching history of Florence, including Cosimo’s reign.

  • Najemy, John M. A History of Florence, 1200–1575. Malden, MA: Wiley Blackwell, 2006.

    DOI: 10.1002/9780470754870

    An important synthesis of several decades of scholarship on Florentine politics and society, with particular emphasis on social groups and political power.

  • Strocchia, Sharon. “Florence.” In Oxford Bibliographies in Renaissance and Reformation. New York: Oxford University Press, 2015.

    Although its main focus is on the fifteenth century and earlier, this online bibliography presents an essential introduction to scholarship on Florence.

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