Cosimo I de' Medici was the second duke of Florence from 1537 until 1569, when he became the first grand duke of Tuscany, a title he held until his death.
Cosimo I de' Medici at about 19 years of age (by Pontormo, c. 1538)
Cosimo I's coronation as Grand Duke of Tuscany, which happened in 1570, Rome.
Official portrait of Cosimo I de' Medici as Grand Duke of Tuscany by Giovanni Battista Naldini