The Duchy of Aquitaine is an intended prize in the campaigns against France, not a place the narrative depicts as reached or conquered. Its importance lies in what its promised recovery meant to Katherine of Aragon: a test of the alliance with Ferdinand II of Aragon and a chance to restore English power in French territory. The plans repeatedly make Aquitaine a destination, while events reveal how little control Katherine has over whether the allied campaign will actually pursue it.

The Intended Theater

In 1512, the proposed campaign would bring the English army together with the Spanish army for an invasion of southwestern France, the rival kingdom, including Guienne and the Duchy of Aquitaine. Katherine expected Ferdinand II of Aragon to honor his promise to march with the English and help win Aquitaine back for England, Catherine's realm. She also believed that he intended to break France’s power by dividing it into smaller kingdoms and duchies, leaving it less able to threaten its neighbors.

Katherine’s confidence rested partly on practical preparation. As the English fleet sailed to join the campaign, she had overseen the provisioning of ships, the stocking of armories, and the equipping of soldiers. Her experience of her parents’ wars had taught her that military success depended on reliable supply. She saw the expedition not only as a military venture but as a coming-of-age in which she could place English resources at her father’s disposal as his ally.

A Renewed Plan, an Unreliable Alliance

The objective returned in the spring of 1513. Under the treaty, Ferdinand II of Aragon was to invade Guienne for England while English forces took Normandy, with Maximilian I, Holy Roman Emperor, joining the northern campaign. Success depended on the three parties attacking at the same time and keeping faith with one another.

That coordination did not hold. In the earlier expedition, English troops waited at Fuenterrabia without being sent into battle, while Ferdinand II of Aragon used their presence to keep French forces occupied as he moved into Navarre. Katherine recognized that her father had concealed his purpose from her. When he later chose peace with France over a war that promised little gain for him, she understood the decision as a defense of his own kingdom, even though it abandoned the campaign she had expected him to support. The English army returned in December in disarray, having received neither the orders nor the reinforcements it needed; two thousand men had been lost to illness.

The Unreached Objective

Aquitaine consequently remains a projected territorial recovery rather than the site of a narrated victory. The second treaty revived the hope of securing it through coordinated action, but Ferdinand’s changing policy had already shown how vulnerable such plans were to the interests of an ally. The narrative gives no account of English or Spanish forces reaching the duchy, taking possession of it, or establishing control there.

For Katherine, the unfulfilled promise marks a shift from the exhilaration of joining her father’s campaign to a sharper understanding of political allegiance. She had imagined that the English fleet and army would help win Aquitaine and strengthen the alliance; instead, the campaign exposed the limits of her influence over Ferdinand II of Aragon. The duchy’s significance is therefore both territorial and political: it is the prize that made the alliance’s promises tangible, and the absent conquest that made their failure unmistakable.