he War of Jenkins' Ear (known as Guerra del Asiento in Spain) is a conflict between Britain and Spain that lasts from 1739 to 1748, with major operations largely ended by 1742.

Its unusual name, which will be coined by Thomas Carlyle in 1858, refers to an ear severed from Robert Jenkins, a captain of a British merchant ship.

Despite stories to that effect, there is no evidence that the severed ear was exhibited before the British Parliament.

The seeds of conflict began with the separation of an ear from Jenkins following the boarding of his vessel by Spanish coast guards in 1731, eight years before the war began.

Popular response to the incident is tepid until several years later when opposition politicians and the British South Sea Company hope to spur outrage against Spain, believing that a victorious war will improve Britain’s trading opportunities in the Caribbean.

Also ostensibly providing the impetus to war against the Spanish Empire is a desire to pressure the Spanish not to renege on the lucrative asiento contract, which givesBritish slavers permission to sell slaves in Spanish America.

The war results in heavy British casualties in North America.

After 1742, the war is subsumed by the wider War of the Austrian Succession, which involves most of the powers of Europe. Peace arrived with the Treaty of Aix-la-Chapelle in 1748.

From the British perspective, the war is notable because it is the first time that a regiment of colonial American troops is raised and placed "on the Establishment" – made a part of the Regular British Army – and sent to fight outside North America.

One of the first actions is the British capture, on November 22, 1739, of a minor silver-exporting town on the coast of New Granada (present Panama), called Puerto Bello in an attempt to damage Spain's finances.

The poorly defended port is attacked by six ships of the line under Admiral Edward Vernon.

The battle leads the Spanish to change their trading practices.

Rather than trading at centralized ports with large treasure fleets, they begin using small numbers of ships trading at a wide variety of ports.

Puerto Bello's economy is severely damaged, and will not recover until the building of the Panama Canal.

In Britain the victory is greeted with much celebration, and in 1740, at a dinner in honor of Vernon in London, the song "God Save the King", now the British national anthem, is performed in public for the first time.

Portobello Road in London is named after this victory and the battle produces the most medals of the eighteenth century.

The conquest of Spain's American empire is widely considered a foregone conclusion.

The success of the Porto Bello operation leads the British in 1740 to send a squadron under Commodore George Anson to attack Spain's possessions in the Pacific, especially in the Philippines; these attacks are largely unsuccessful.