Separate issue, with "Prix Trois Francs" lower right.

After Columbus's discovery of America in 1492, Cadiz soon became the home of the Spanish treasure fleet, and a target for foreign countries seeking to strike at the heart of the Spanish Empire. Sir Francis Drake famously destroyed much of the Spanish fleet there in 1587; it was blockaded by the British in 1797-1798, and bombarded by them in 1800.

In 1808 "Cadiz assumed a pivotal role in the relationship with Spain's new allies. When Napoleon Bonaparte invaded the Iberian Peninsula, first to enforce the Continental System against Great Britain, and shortly afterwards, to put his own Brother on the Spanish Throne, he did not realize the difficulty of his task. Of all the other provinces and cities, only Cadiz remained free of French domination. It became the center of the new Revolutionary government and the focus for allied cooperation in Spain. Blessed with a good harbor and natural defensive barriers, Cadiz proved an ideal location for allied cooperation. It was besieged for thirty months, far longer than any other city would have to endure, and was never taken. Cadiz, along with Andalusia, served as a source of strategic consumption of -the French Army in the Peninsula, and contributed directly, to the loss of Spain for the French... The unsuccessful French siege of Cadiz is one of the most important military actions in the Peninsula. The successful allied defense of this key city made possible the survival of the revolutionary Spanish Government and facilitated the funneling of British arms, money, and soldiers into Spain for its fight against the French. Had Cadiz fallen, and with it the 1812 liberal constitution drafted by the Cortes, the latter history of Spain would have been far different. Had the French taken the last "free" city in Spain, the vicious guerrilla war against her troops may have lacked both reason and coordination in Andalusia. The British government would have had no cliental point of coordination or a secure base of operations. Cadiz served not only as the capital of the Spanish government, it also served as the focal point for Peninsular support operations for the British outside of Lisbon" (Herson)

After a month of vacillating, at the beginning of June, 1808, the Spanish of Cadiz officially revolted, turning their canon on the French fleet, under the command of Rear Admiral Maurice Rosily, in their harbour. After about ten days the French had capitulated, and the first naval victory of the Spanish Revolution against the Bonaparte regime had been won.

Britain was the ultimate victor of the Peninsular War in 1814, when Napoleon abdicated. However the effects of the battle were felt in Europe and America for many decades to come.