William Ewart Gladstone was the Liberal prime minister of the United Kingdom of Great Britain and Ireland on four separate occasions between 1868 and 1894. He was noted for his moralistic leadership and his emphasis on world peace, economical budgets, political reform and efforts to resolve the Irish question. Gladstone saw himself as a national leader driven by a political and almost religious mission, which he tried to validate through elections and dramatic appeals to the public conscience. His approach sometimes divided the Liberal Party, which he dominated for three decades. Finally Gladstone split his party on the issue of Irish Home Rule, which he saw as mandated by the true public interest regardless of the political cost.

The Treaty of Washington was a treaty signed and ratified by the United Kingdom and the United States in 1871 during the first premiership of William Gladstone and the presidency of Ulysses S. Grant. It settled various disputes between the countries, including the Alabama Claims for damages to American shipping caused by British-built warships, as well as illegal fishing in Canadian waters and British civilian losses in the American Civil War. It inaugurated permanent peaceful relations between the United States and Canada, and also with the United Kingdom. After the arbitrators endorsed the American position in 1872, Britain settled the matter by paying the United States $15.5 million, ending the dispute and leading to a treaty that restored friendly relations between Britain and the United States. That international arbitration established a precedent, and the case aroused interest in codifying public international law.