| Honorific Prefix: | The Right Honourable |
| The Count of Cacilhas | |
| Office: | British Ambassador to the Russian Empire |
| Term Start: | 1881 |
| Term End: | 1884 |
| Predecessor: | The Earl of Dufferin |
| Successor: | Sir Robert Morier |
| Office1: | British Envoy Extraordinary and Minister Plenipotentiary to the United States |
| Term Start1: | 1867 |
| Term End1: | 1881 |
| Predecessor1: | Sir Frederick Bruce |
| Successor1: | Lionel Sackville-West |
| Office3: | British Envoy Extraordinary and Minister Plenipotentiary to the Emperor of Brazil |
| Term Start3: | 1865 |
| Term End3: | 1867 |
| Predecessor3: | William Dougal Christie |
| Successor3: | George Buckley-Mathew |
| Office4: | British Minister Plenipotentiary to the Argentine Confederation |
| Term Start4: | 1859 |
| Term End4: | 1865 |
| Predecessor4: | William Dougal Christie |
| Successor4: | George Buckley-Mathew (as Minister to the Argentine Republic) |
| Birth Name: | Edward Thornton |
| Birth Place: | London |
| Death Place: | London |
| Education: | King's College London |
| Alma Mater: | Pembroke College, Cambridge |
| Parents: | Edward Thornton, 1st Count of Cacilhas Wilhelmina Kohp |
| Relations: | Edward Thornton (grandson) |
Sir Edward Thornton, 2nd Count of Cacilhas, (13 July 1817 – 26 January 1906) was a British diplomat who held posts in Latin America, the Ottoman Empire, the Russian Empire, and served for fourteen years as Minister to the United States.
Thornton was born in London on 13 July 1817. He was the eldest son of Sir Edward Thornton, 1st Count of Cacilhas, also a diplomat, who for many years held the post of British Minister to Portugal.
Thornton was educated at King's College London, and at Pembroke College, Cambridge.[1] [2]
He entered the diplomatic service as attaché to the mission at Turin in the Kingdom of Sardinia in 1842, filled the same position in Mexico in 1845, and was made Secretary of Legation in that Capital in 1853.[1] [2] Thornton did much to forward the conclusion of the Treaty of Guadalupe Hidalgo in 1848.[2]
On his father's death in 1852,[3] Thornton became 2nd Count of Cacilhas (also "Cassilhas").[4] Also in 1852, he was appointed Secretary of Legation at Buenos Aires, and chargé d'affaires to Uruguay in 1854.[2] He was appointed Minister to the Argentine Republic in 1859, and to the Empire of Brazil in 1865.[1]
Thornton's diplomacy was praised in a House of Commons debate on the Christie Question, William "Seymour" Vesey-FitzGerald calling him "a gentleman who knows how to conciliate... [he knows] that it is not his duty to 'read lessons' to foreign Governments", his behaviour being contrasted with that of William Dougal Christie, British consul in Brazil.[5]
After the war scare with Brazil was averted, another major geopolitical conflict embroiled South America – the Paraguayan War. Brazil, Argentina and Uruguay signed the Treaty of the Triple Alliance, which united all three nations against Paraguay.[6] According to British historian Pelham H. Box, Argentine foreign minister Rufino de Elizalde informed Thornton that the Argentine government had no wish to annex Paraguay, but hoped that in the long term Paraguay might voluntarily join the Argentine Confederation (as was contemplated by Article 13 of the Argentine Constitution). He also informed Thornton that the Argentine Congress feared the provisions in the Treaty might prevent such an occurrence.[7] After the war concluded, Thornton was withdrawn from his position, having concluded several agreements during his tenure.[8] [9]
Thornton's lengthiest assignment was as Minister to the United States, a position he held for fourteen years (1867–1881).[1] In 1871, Thornton served as a member of the commission on the Alabama Claims, and was appointed Privy Councilor.[1] Thornton served in 1873 as an arbitrator in the commission on the Mexican and United States Claims.[1] [2]
In 1881, he was appointed Ambassador at St. Petersburg.[1] [2] For his services Thornton was invested Knight Grand Cross of the Order of the Bath in 1883.[1] [2] A year later Thornton received his last appointment, Ambassador at Constantinople, a position he held for three years before retiring "on a pension" in 1887.[1] [2]
In 1854, Thornton married Mary Jane (Maitland) Melville (1827–1907), at St Peter's Church, Eaton Square.[10] Mary, the widow of Andrew Melville of Dumfries and a daughter of John Maitland and Frances MacKenzie (Dalyell) Maitland.[11] Together, they were the parents of:[12]
After a lengthy illness, Thornton died at his London residence, 5 Tedworth Square, on 26 January 1906.[1] He is buried in Brookwood Cemetery. As his son and heir, diplomat Edward Thornton (born 1856), had died in 1904,[13] the title of Count of Cacilhas passed to his grandson, Edward Thornton.[4]