The only Caravaggio work owned by the Museo del Prado, David with the Head of Goliath, underwent new technical studies and restoration in 2023. The result has helped to clarify the work’s original luminosity and compositional meaning. New X-rays have revealed the existence of a pentimento on David’s right ankle, where the master initially intended to paint a type of bandage, perhaps evoking those used by ancient boxers. At the same time, a previously unknown inventory number, 449, has been detected in the underlying layer of the lower left corner, which allows the painting to be located in the Buen Retiro palace in Madrid in 1700, well before its first known location to the present. A review of the painting’s records in other Spanish inventories from the eighteenth and nineteenth centuries also reveals that it was subject to re-enlargements, likely intended to serve in displays based on symmetry in royal palaces. Thanks to several old copies examined, this enlargement process can be visually followed, although today the work is presented in the Prado Museum without any of these additions. Finally, a comparison with one of these copies suggests that Caravaggio’s original composition included a remarkable development of the upper and lower margins, with the sword hilt in its entirety at the bottom and Goliath’s entire foot at the top.