Francis, Duke of Guise, played a pivotal role in the capture of Calais, which was the last remaining territorial possession of England on the European continent. Following years of military conflict during the Italian Wars and ongoing hostilities between England and France, the French forces sought to reclaim the strategic port city. The siege took place in the backdrop of heightened tensions from the broader context of the ongoing Habsburg-Valois Wars and the English Reformation, which diverted England's focus from its overseas territories.

The successful military action began with an intensive siege that overwhelmed the Spanish and English defenders. Despite earlier resistance, the coordinated efforts of Guise's troops proved decisive. As French forces breached the city, fears of retribution and violence spread among the defenders, leading to swift capitulation. The fall of Calais signified a remarkable shift in the balance of power, marking the end of England's long-standing claims to French territories that had persisted since the Hundred Years' War.

Following the capture, Calais became a focal point of French strength and a testament to the resurgence of French dominance in the region. The removal of this English outpost significantly altered the geopolitical landscape of Northern Europe. Calais would remain a French possession, thus reframing the narrative of English claims in France and reshaping diplomatic and military strategies for both nations in the years to come.