Antonio de Ulloa, a Spanish naval officer and scientist, was captured by the British and eventually elected to a London society.
Antonio de Ulloa y de la Torre-Giralt, FRS, FRSA, KOS (12 January 1716  3 July 1795) was a Spanish naval officer, scientist, and administrator. The ship upon which Ulloa was travelling was captured by the British Royal Navy, and he was taken to England as a prisoner of war. He was elected as a Fellow of the Royal Society of London in December 1746. 
