Sir Vincent Arthur Henry McMahon GCMG GCVO KCIE CSI KStJ (28 November 1862 – 29 December 1949) was a British Indian Army officer and diplomat who served as the Foreign Secretary in the Government of India from 1911 to 1915 and as the High Commissioner in Egypt from 1915 to 1917.

[2] As the Foreign Secretary McMahon conducted the tripartite negotiations between Tibet, China and Britain that led to the Simla Convention.

In Egypt, McMahon was best known for the McMahon-Hussein Correspondence with Hussein bin Ali, Sharif of Mecca, and the Declaration to the Seven in response to a memorandum written by seven notable Syrians.

[citation needed] It has been reported that he was captured by the British during the Walcheren Campaign of 1809 and sent to England, but was later able to return to France where, in June 1815, he eventually died fighting at either Ligny or Waterloo.

[citation needed] In 1911, the Viceroy Lord Hardinge appointed McMahon as the Foreign Secretary to the Government of India.

[10][12] In 1915, McMahon was sent to replace Sir Milne Cheetham, briefly acting for Lord Kitchener, who had become War Secretary in London, in the post of High Commissioner in the Sultanate of Egypt.

With the approval of Kitchener and Foreign Secretary Sir Edward Grey, McMahon began a long correspondence with Husayn bin Ali, Sharif of Mecca, the Ottoman-appointed ruler of the Hijaz, to use the Bedouin tribes under his control to support the Egyptian Expeditionary Force in overthrowing the Ottomans.

[14] Sir Gilbert Clayton, Aubrey Herbert, Storrs and others of the intelligence community approved of McMahon's pro-Arabist policy from 1916 onwards.

The British decision to land an invasion force in the Dardanelles, instead of Alexandretta, and to promise the French Syria under the Sykes-Picot Agreement, irritated McMahon.

On 23 November 1917, following the October Revolution, the Bolsheviks released copies the Sykes–Picot Agreement and other secret treaties, publishing full texts in Izvestia and Pravda.

In 1909, at the church of St George's, Hanover Square, London, she married Henry A. Hetherington, of Berechurch Hall, Colchester.