Cosimo I de' Medici (1519-1574) was the first Grand Duke of Tuscany, ruling from 1537 to 1574, during the waning days of the Renaissance.
Having taken power from the Republic of Florence after being elected as a supposed figurehead, he restored the power of the Medici, who thereafter ruled Florence until the last of the Medici Grand Dukes, Gian Gastone de' Medici (1671-1737). The governmental structures he set up endured past that, when it was absorbed into the Austro-Hungarian Empire.
Among his many accomplishments were the creation of the Uffizi, originally intended to house the government, and now one of the world's great art galleries; the creation of the Florentine navy, which played a key role at the battle of Lepanto; the expansion of Florence to control most of Tuscany, including Siena; taking over the Pitti Palace as a home for the Medici and finishing it off; the creation of the magnificent Boboli Gardens behind the Pitti; the promotion of the University of Pisa; and a host of other accomplishments in the economic, architectural and artistic spheres, including supporting Vasari and Cellini.
A large equestrian state of him in bronze, by Giambologna, erected in 1598, still stands today in the Piazza della Signoria, the main square of Florence.