Following the occupation of Seville, Cádiz became the Spanish seat of power,[7] and was targeted by 70,000 French troops under the command of the Marshals Claude Victor and Nicolas Jean-de-Dieu Soult for one of the most important sieges of the war.

In 1812, the Battle of Salamanca eventually forced the French troops to retreat from Andalusia, for fear of being cut off by the Coalition armies.

Napoleon's advisor, the Duke of Cadore, recommended that the ports of Europe be closed to the British, stating that "Once in Cadiz, Sire, you will be in a position either to break or strengthen the bonds with Russia".

The last person to leave was to be Maj Lefebure of the Royal Engineers, whose job was to fire a mine to destroy the fort, but he was killed by a cannon shot.

The ensuing bombardment of the Spanish coastal city involved some of the largest artillery pieces in existence at the time, including Grand Mortars, which were so large they had to be abandoned when the French eventually retreated, and fired projectiles to distances previously thought impossible, some up to 5 kilometres (3 miles) in range.

[4] (The Grand Mortar was placed in St. James's Park in London as a gift to the British in honour of the Duke of Wellington.

[12] On many occasions, the French were forced to send escorts of 150–200 men to guard couriers and supply convoys in the hinterland.

This captured fort also provided the French with a vantage point from which to shell ships coming in and out of the besieged Spanish port.

This Anglo-Spanish force was under the overall command of Spanish General Manuel la Peña, with the British contingent being led by Lieutenant-General Sir Thomas Graham.

An attempt by Victor to crush the small Anglo-Spanish garrison at Tarifa over the winter of 1811–1812 was frustrated by torrential rains and an obstinate defence, marking an end to French operations against the city's outer works.