Armas antárticas y hechos de los famosos capitanes españoles que se hallaron en la conquista del Perú [Antarctic Arms and Deeds of the Famous Captains who were Present at the Conquest of Peru] (c. 1608–09) is, from the outset, more ambitious in scope than the two Arauco epics analysed thus far. Moving beyond the war in Chile, it attempts to encompass in twenty cantos the history of conflict across the ‘Antarctic’ sphere of the Viceroyalty of Peru, from the Magellan Strait to the jungle of Panama. Chronologically, the narrative commences with Pizarro's overthrow of Atahualpa in 1532, and ends with the exploits of Thomas Cavendish in 1587, with one extended flashback to the pre-Hispanic past and several flash-forwards to ongoing military encounters along the frontiers and coasts of the Viceroyalty.

Within this broad panorama, the narrative focus and expectations continually shift as one conflict gives way to another. A reader led by the poem's full title to expect a poem centred on the wars of conquest would soon be disappointed. Only the opening two cantos, which promise to recount ‘Las armas y proezas militares | de españoles cathólicos valientes’ [the arms and military prowess of valiant Catholic Spaniards] (I. 1), cover the conquest of the Inca Empire and the civil wars between Spaniards that followed. These wars are recounted with a verve and complexity which bring many of the underlying questions of Ercilla and Oña to a new context. Debates surrounding the justice of the conquest and its conduct, the problem of rebellion, and the sway of fortune, virtue and Providence in human affairs are all aired in concentrated form. No sooner are the questions raised, however, than they find an equally summary closure: the second canto ends with the cycles of both conquest and rebellion complete and the realms of Peru serenely enjoying the fruits of peace.

In the third canto, the poem starts afresh, with a new epic proem, an invocation of the muse Erato, and an epic question: ‘¿quién perturbó al Pirú de paz el trato, | quién guerras incitó y Marte sangriento?’