König Philipp III.(1578-1621) von Spanien, Bildnis in ganzer Figur als General der Infanterie (Im Hintergrund: Die Belagerung von Ostende 1601-1604)

This monumental full-length portrait of Philip III as General of the Infantry, dated 1601 and held at the Kunsthistorisches Museum, is one of the most ambitious works Pantoja produced: a full state portrait that shows the king in armour against a background depicting the Siege of Ostend (1601–1604), the long and costly engagement that dominated the early years of his reign. The siege — in which Spanish forces attempted to retake the strategically vital Netherlands port from the Dutch — became a defining event of the Twelve Years' War period, and its inclusion in the background of a royal portrait amounted to a political statement about Spanish military ambition and royal command. Philip III rarely exercised personal military authority, leaving strategy and governance to Lerma, but the portrait image demanded the fiction of martial leadership. Pantoja constructs this fiction with skill: the armoured king stands with the calm authority of a commander, the distant battle smoke and siege works framed as backdrop to sovereign competence.

The composition's ambition requires Pantoja to manage both the foreground figure in gleaming armour and a detailed landscape battle scene. The armour is rendered with exceptional metallic precision, while the distant siege scene employs aerial perspective — cooler and bluer tones for distant elements — that Pantoja rarely used in his usual dark-ground court portraits. The contrast between the still, armoured figure and the mobile background creates a studied drama.