War of Jenkins' Ear starts: British Prime Minister Robert Walpole, reluctantly declares war on Spain.

The War of Jenkins's Ear (known as Guerra del Asiento in Spain) was a conflict between Britain and Spain lasting from 1739 to 1748, mainly in New Granada and among the West Indies of the Caribbean Sea, with major operations largely ended by 1742. Its name, coined by British historian Thomas Carlyle in 1858, refers to Robert Jenkins, a captain of a British merchant ship, whose ear was cut off by sailors of the Spanish coast guard when they boarded his ship to search for contraband. Seven years later, in support of mongering for war, Jenkins was paraded before the British Parliament, without his ear.

The ostensible casus belli began with the maiming of Jenkins following the boarding of his vessel by Spanish coast guards in 1731, eight years before the war began. Popular response to the incident was tepid until several years later, when opposition politicians and the British South Sea Company played it up, hoping to spur outrage against Spain, believing that a victorious war would improve Britain's trading opportunities in the Caribbean. In addition, the British wanted to keep pressure on Spain to honour their lucrative asiento contract, which gave British slave traders permission to sell slaves in Spanish America. The Spanish refer to this asiento in their name for this war.British attacks on Spanish possessions in Central America resulted in high casualties, primarily from disease. After 1742, the war was subsumed by the wider War of the Austrian Succession, which involved most of the powers of Europe. Peace arrived with the Treaty of Aix-la-Chapelle in 1748.