Britain went to war with Spain over a merchant captain's severed ear

In 1731, Spanish coast guards boarded captain Robert Jenkins's ship near Cuba and cut off his ear, accusing him of smuggling. The incident was mostly forgotten until 1738, when opposition politicians revived it in Parliament to push Britain toward war with Spain over Caribbean trade rights. The resulting conflict, fought from 1739, is still known today by his name.

— Standard historical accounts, War of Jenkins' Ear — Conflict began 1739, following the 1731 Jenkins incident