The Great Siege of Gibraltar began in 1779, marking one of the most significant military confrontations during the American Revolutionary War. Gibraltar, a British Overseas Territory perched at the southern tip of the Iberian Peninsula, served as a vital naval chokepoint for maritime traffic entering and exiting the Mediterranean Sea. The strategic importance of Gibraltar led Spain to attempt to reclaim the territory, which had been under British control since 1704. In June 1779, Spain allied with France to initiate a comprehensive siege against the British garrison stationed in Gibraltar, which was led by General George Eliott.

The siege was characterized by numerous assaults and a prolonged blockade intended to starve the British defenders into submission. Spanish and French forces employed various siege technologies, including heavy artillery and naval blockades, hoping to exploit the defensive weaknesses of Gibraltar. The defenders, using the fortifications and their well-prepared military strategies, managed to hold off these assaults for years despite facing challenges such as lack of supplies and manpower. Notably, British naval success in the surrounding waters enabled them to intermittently resupply their forces.

The Great Siege culminated in several historic events, including the famous 'sorties' where British troops launched counter-attacks against the besieging forces. Despite being significantly outnumbered, the resilience and determination of the British garrison would allow them to withstand the siege until its end in 1783, significantly impacting the war's dynamics in the region. The eventual lifting of the siege not only cemented British control over Gibraltar but also served as a testament to the effectiveness of defensive military operations in prolonged engagements.