Dressed in early seventeenth-century style, the King of Spain (1605-1665) is shown as a youth, while still a prince. The baton and his decisive way of holding the reigns mark a classic attitude of power that gives the figure its appropriate sense of majesty.

It was probably made by Pietro Tacca, given its similarity to other sculptures of his. The hrose follows the model of the famous ancient statue of Marcus Aurelius that formerly stood in the Piazza del Campidoglio in Rome, as well as Daniele de Volterra's variation on it for his monument to Henri II of France.