The Equestrian Monument of Cosimo I is a bronze equestrian statue by Giambologna, erected in 1594 in the Piazza della Signoria in Florence.
Having achieved by the 1580s a complete mastery of the human form, Giambologna turned to the subject that had fascinated the ancient Greeks and Romans almost as much, the horse. He addressed the subject with a scientific approach and created his masterpiece in bronze, the equestrian statue of Cosimo I, Grand Duke of Tuscany. It was an immediate success and was replicated on the much reduced scale of statuettes, with a variety of different riders. A full-size variant showing Ferdinando I de' Medici was commissioned shortly afterwards for Piazza Santissima Annunziata; others followed for the kings of France and Spain.

His chosen model of horse was compact and rotund, with a short body and well-rounded rump, its contours enlivened by the raised front hoof and wildly curling mane, as well as by the sinuous tail. The lively character and alertness of the beast are conveyed by its swollen veins, rolling eyes and pricked-up ears.

This monument was commissioned by Cosimo's son Ferdinando I from the sculptor Giambologna, who also completed the Rape of the Sabines in the adjacent Loggia dei Lanzi. The Cosimo statue stands in front of the north corner of the Palazzo della Signoria, the northernmost of the row of statues, adjacent to the Fountain of Neptune (1563) by Ammannati, that had been commissioned by Cosimo himself. Together this duo celebrates the land and sea ambitions of Cosimo. The base of the statue has reliefs with scenes from the life of Cosimo, including his coronation in Rome as Grand-Duke in 1570 and his entrance into Siena as a ruler (1557) after his victory over that republic.[2]

The posture of the trotting horse in this statue is similar to those of prior statues, with right leg raised, however unlike Marcus Aurelius, Cosimo uses stirrups and his horse shows the restraint of the bridle, albeit without much tension. Cosimo, like Gattemalata, holds a military baton, armor, and sheathed sword.

Some sources state the man and horse were cast separately, and the combined weight of the two was 23 thousand pounds.[3] A few decades hence, Ferdinando I would have his own Equestrian monument in Piazza dell'Annunziata.[4]

In 1591 the horse was ready and had been cast in a single range. In 1594 the work was finally completed, with the figure of the Grand Duke and with the marble pedestal, on which three bas-reliefs depicting salient episodes of his life were placed: L'elezione a duca (The election as duke, which took place in 1537), La conquista di Siena (The conquest of Siena ( 1555) and Il conferimento del titolo di Granduca (The conferral of the title of Grand Duke (1569), each bas-relief with an explanatory cartouche at the top, in Latin.