The Siege of Cádiz began in 1810 as part of the Peninsular War, which saw British, Spanish, and Portuguese forces opposing the French Empire's expansion under Napoleon. Cádiz, being one of Spain's major ports and a stronghold of the resistance, faced a formidable blockade by French troops. By 1812, the situation was dire for the besieged inhabitants, who endured severe shortages of food and supplies. The coalition of forces recognized the need to lift the siege not only to bolster the morale of the Spanish people but also to assert their military strength against the French.

On 24th August 1812, the allied forces launched a decisive operation combining land and naval capabilities. Led by British General Sir Arthur Wellesley, later known as the Duke of Wellington, and Spanish General Francisco de la Peña, the operation aimed at breaking the French stranglehold over the city. The plan involved coordinated attacks and strategic maneuvers across land and sea, showcasing cooperation among the allied troops. This concerted effort culminated in a successful attack on French positions, enabling the allied forces to enter Cádiz and effectively lifting the siege.

The liberation of Cádiz marked a significant turning point in the Peninsular War. It revitalized the Spanish resistance against French occupation and encouraged further military cooperation among Spain, Britain, and Portugal. This success not only provided a logistical and moral boost but also solidified the strategic importance of Cádiz as a base for future operations in the Iberian Peninsula. The lifting of the siege symbolized a critical moment of unity for the allies against a common enemy, reversing French advances in the region.