Arthur James Balfour, 1st Earl of Balfour, KG, OM, PC, DL (25 July 1848 – 19 March 1930) was a British Conservative politician and statesman. He served as the Prime Minister of the United Kingdom from July 1902 to December 1905 and as Leader of the Conservative Party from his appointment as Prime Minister to November 1911. He was a Member of Parliament from 1874–1922 and served as Foreign Secretary in David Lloyd George's coalition government 1916-1919.
He authored the Perpetual Crimes Act (1887) (or Coercion Act) aimed at the prevention of boycotting, intimidation and unlawful assembly in Ireland during the Irish Land War, and was Prime Minister at a time when his party and government became divided over the issue of tariff reform. Later, as Foreign Secretary, he authored the Balfour Declaration of 1917, which supported the establishment of a Jewish homeland in Palestine.
Arthur Balfour was born at Whittingehame, East Lothian, Scotland, and was the eldest son of James Maitland Balfour (1820–1856) and Lady Blanche Gascoyne-Cecil (d. 1872, aged forty-seven). His father was a Scottish MP; his mother, a member of the Cecil family descended from Robert Cecil, 1st Earl of Salisbury, was the daughter of the 2nd Marquess of Salisbury and a sister to the 3rd Marquess, the future Prime Minister. His godfather was the Duke of Wellington, after whom he was named. He was the eldest son, the third of eight children, and had four brothers and three sisters. Arthur Balfour was educated at the Grange preparatory school in Hoddesdon, Hertfordshire (1859–1861), Eton (1861–1866) where he studied with the influential Master William Johnson Cory, and Trinity College, Cambridge (1866–1869), where he read Moral sciences, graduating with a Second-Class Honours Degree. His younger brother was the renowned Cambridge embryologist Francis Maitland Balfour (1851–1882).