US statesman and sixth president (1825–9), born in Braintree (later Quincy), Massachusetts, USA, the son of John Adams and Abigail Adams. He was reared for public service, travelled in childhood on his father’s diplomatic missions, and at age 14 was private secretary to the American envoy at St Petersburg. He graduated from Harvard (1787) and was admitted to the bar (1790). Successively ambassador to The Hague, London, Lisbon, and Berlin, he was elected as a Massachusetts Federalist to the US Senate (1803), but his support of Jefferson (1806) outraged New England Federalists and he lost his seat (1808). He served as ambassador to Russia (1809), as a member of the commission to negotiate peace with Great Britain (1814), and as ambassador to Great Britain (1815–17). A brilliant secretary of state under President Monroe (1817–25), he negotiated with Spain the treaty for the acquisition of Florida (1819) and wrote a good deal of the ‘Monroe Doctrine’ (1823). In 1824 he won the presidential election over Andrew Jackson, but only after a close vote in the House of Representatives. Cold in manner and too independent to command a following, he was an ineffective president and lost to Jackson in 1828. In 1831 he entered the US House of Representatives, where for the rest of his life he was a champion of the anti-slavery faction, and in 1841 successfully defended the African mutineers of the slave ship Amistad. He suffered a stroke while sitting in the House and died two days later.