Henry Charles Keith Petty-Fitzmaurice, 5th Marquess of Lansdowne, KG, GCSI, GCMG, GCIE, PC (14 January 1845 – 3 June 1927), was a British statesman who served successively as Governor General of Canada, Viceroy of India, Secretary of State for War and Secretary of State for Foreign Affairs.

[2] His maternal grandfather, Count Charles de Flahaut, was an important French general to Napoleon Bonaparte, and a member of his family.

[3] His maternal great-grandfather, George Elphinstone, 1st Viscount Keith, was also the Admiral who prevented Napoleon's escape from France after the Battle of Waterloo, and who received and supervised his final surrender to St. Helena in 1815.

[7] At one of his inherited properties, Derreen House (Lauragh, County Kerry, in the present-day Republic of Ireland), Lord Lansdowne started to develop a great garden from 1871 onwards.

He was a member and trustee of the Brooks's Club in London, along notable members such as Spencer Cavendish, 8th Duke of Devonshire of Chatsworth House, Lord Rosebery of Mentmore Towers, and Baron Lionel de Rothschild of Tring Park, son of Nathan Mayer of Gunnersbury Park, and grandson of Mayer Amschel, founder of the House of Rothschild.

The North-West Rebellion of 1885 and the controversy caused by its leader, Louis Riel, posed a serious threat to the equilibrium of Canadian politics.

[13] The same area was previously used by the past Viceroy of Canada, John Campbell, 9th Duke of Argyll, and his wife, Princess Louise, the daughter of Queen Victoria.

[14] Lansdowne proved to be an adept statesman in helping to settle a dispute over fishing rights between Canada and the United States in 1886–1887.

In Quebec, he was very popular, as he spoke French fluently, which gained him the admiration of French-Canadians, and a big round of applause during his first speech.

Lord Lansdowne also made multiple speeches at the Citadelle of Quebec, near Château Frontenac, and joined the Montreal Winter Carnival, making him and his wife, the first vice-royal couple to skate at that event.

[14] Lansdowne departed Canada "with its clear skies, its exhilarating sports, and within the bright fire of Gatineau logs, with our children and friends gathered round us" to his regret.

In December 1888 he was appointed GCSI [17] and GCIE [18] The office, which he held from 1888 to 1894,[1] was offered to him by the Conservative prime minister, Robert Gascoyne-Cecil, 3rd Marquess of Salisbury of Hatfield House, and marked the pinnacle of his career.

His biographer, P. B. Waite, considers that he was unjustly criticised for British military failures, but ever the good minister, he took full responsibility and said nothing.

[1][13] After the Unionist victory in the general election of October 1900, Salisbury reorganised his cabinet, gave up the post of Foreign Secretary and appointed Lansdowne to replace him.

As British Foreign Secretary, he approved of protectorate Commissioner Wilson's 1901 Anglo-Ankole agreement in Uganda, he also signed the 1902 Anglo-Japanese Alliance at his London home, the back half of which still exists as the Lansdowne Club, and negotiated the 1904 Anglo-French Entente Cordiale with French Foreign Minister Theophile Delcassé.

According to G. W. Monger's summary of the Cabinet debates in 1900 to 1902:Chamberlain advocated ending Britain's isolation by concluding an alliance with Germany; Salisbury resisted change.

With the new crisis in China caused by the Boxer rising and Landsdowne's appointment to the Foreign Office in 1900, those who advocated a change won the upper hand.

In 1917, having discussed the idea with colleagues for some time with no response, he published the controversial "Lansdowne letter", which called for a statement of postwar intentions from the Entente Powers, and an end to the war on the basis of a return to the status quo ante.