On 1[4] or 2[5] August 1537 (both dates are given in sources), near the Tuscan village of Montemurlo, the forces of the newly installed Duke Cosimo I of Florence defeated a hastily organized army of those who wished to overthrow the Medici and restore the Republic of Florence.[6] Following the battle, Cosimo's bloody vengeance on all those who opposed Medici rule effectively ended organized opposition to his family in Florence. The victory led to the decision of Emperor Charles V to formally recognize Cosimo as Duke of Florence on 30 September 1537.[7]
^Villari, Pasquale (1911). "Medici" . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 18 (11th ed.). Cambridge University Press. pp. 31–41, see page 36, middle of fourth para. 'On the evening of the 31st of July Vitelli marched towards Prato with seven hundred picked infantry and a band of one hundred horse, and on the way fell in with other Spanish foot soldiers who joined the expedition.
^Young, Colonel G. F. (1930). The Medici. [Whitefish, MT]: Kessinger Publications. p. 553. ISBN978-1-4191-8129-0. Retrieved 7 December 2011. 1st August 1537