{"record":{"aliases":[],"appointmentIds":["united-kingdom-541e5bee717c2d"],"appointmentsDataset":"https://chanceries.org/diplomats.json","archivalSources":[],"canonicalUrl":"https://chanceries.org/diplopedia/people/henry-unwin-addington-6727f8416c/","countrySlug":"united-kingdom","entityId":"https://chanceries.org/diplopedia/people/henry-unwin-addington-6727f8416c/#person","eventIds":[],"expandedParagraphs":["Henry Unwin Addington was born in 1790 into a family connected with British government: his uncle was Prime Minister Henry Addington, later Lord Sidmouth. Educated at Winchester, he joined the Foreign Office in 1807 and served in Switzerland and Copenhagen before Washington. He became secretary of the American legation and took charge during Stratford Canning's absence in the early 1820s.","One of his principal Washington efforts concerned the proposed convention against the Atlantic slave trade. In May 1824 Addington pressed Secretary of State John Quincy Adams for prompt ratification, stressing that Parliament had already declared British participation in the trade piracy. He even detained the packet ship that had brought the act so that it could carry the ratified agreement back to London. Adams recorded his anxiety about Senate opposition and a separate complaint about American duties on iron.","The Senate amended the agreement, including removal of American waters from the area where reciprocal searches could occur. Britain rejected that version. Addington renewed discussion of a British counterproposal in 1825, but the negotiation failed to produce a convention in force.","His later assignments included negotiations with the United States in London, the German federal diet at Frankfurt, and the mission in Madrid. Palmerston recalled him from Spain in 1833. He returned to senior government service under Aberdeen and served as permanent undersecretary at the Foreign Office from 1842 to 1854. He became a privy councillor on retirement and died on 6 March 1870."],"id":"united-kingdom:henry unwin addington","identifiers":{},"legacyPersonIds":[],"legacyUrl":"https://chanceries.org/diplomat-6727f8416c941ef978b4.html","name":"Henry Unwin Addington","notes":[],"paragraphSources":[["addington-dnb","addington-ha"],["addington-convention","addington-diary"],["addington-dubois"],["addington-dnb","addington-uvic"]],"profileUrl":"diplomat-6727f8416c941ef978b4.html","relatedEvents":[],"relatedPeople":[{"certainty":"documented","name":"Stratford Canning","note":"Legation secretary who took charge during Canning's absence.","profileUrl":"diplomat-de7817e83722353a3f78.html","sourceIds":["addington-ha"],"targetId":"united-kingdom:stratford canning","type":"collaborator"}],"relationships":[{"certainty":"documented","note":"Legation secretary who took charge during Canning's absence.","sourceIds":["addington-ha"],"targetId":"united-kingdom:stratford canning","type":"collaborator"}],"researchStatus":"reviewed","reviewedOn":"2026-10-28","revision":"0dced910132aede2","sources":[{"accessedOn":"2026-10-28","date":null,"id":"addington-dnb","locator":"Complete entry","publisher":"Dictionary of National Biography / Wikisource","title":"Addington, Henry Unwin — Dictionary of National Biography","type":"reference","url":"https://en.wikisource.org/wiki/Dictionary_of_National_Biography,_1885-1900/Addington,_Henry_Unwin"},{"accessedOn":"2026-10-28","date":"2002-03-01","id":"addington-ha","locator":"Public introductory paragraph only","publisher":"Joseph Smith, Historical Association","title":"‘Savages and rattlesnakes’: Washington, District of Columbia: A British Diplomat's view 1823–5","type":"scholarship","url":"https://www.history.org.uk/publications/categories/301/resource/605/savages-and-rattlesnakes-washington-district-of"},{"accessedOn":"2026-10-28","date":"1824-05-21","id":"addington-convention","locator":"No. 374, pp. 344–347; Addington to Adams, 16 May 1824","publisher":"American State Papers, Foreign Relations / ibiblio","title":"Suppression of the Slave Trade","type":"primary-record","url":"https://www.ibiblio.org/pha/USN/1824/18240521Slavery.html"},{"accessedOn":"2026-10-28","date":"1824-05-14","id":"addington-diary","locator":"Diary pp. 317–318","publisher":"Massachusetts Historical Society, Primary Source Cooperative","title":"John Quincy Adams diary, 14 May 1824","type":"primary-record","url":"https://www.primarysourcecoop.org/publications/jqa/document/jqadiaries-v34-1824-05-p301--entry14"},{"accessedOn":"2026-10-28","date":"1896","id":"addington-dubois","locator":"Appendix B, pp. 266–270","publisher":"W. E. B. Du Bois / ibiblio","title":"The Suppression of the African Slave-Trade to the United States of America, 1638–1870","type":"scholarship","url":"https://www.ibiblio.org/pha/USN/DuBoisAppB.html"},{"accessedOn":"2026-10-28","date":null,"id":"addington-uvic","locator":"Biographical entry","publisher":"University of Victoria, Colonial Despatches","title":"Addington, Henry Unwin","type":"reference","url":"https://bcgenesis.uvic.ca/old/2.0/addington_hu.html"},{"accessedOn":"","date":"","id":"mission-e07a3013dde512fd0ad6","locator":"","publisher":"","title":"Henry Unwin Addington — mission record (1823–1825)","type":"Mission record","url":"https://books.google.com/books/about/Youthful_America.html?id=xV_1wStD0ncC"}],"topics":["slave trade suppression","maritime search","Foreign Office administration"]},"schemaVersion":1}