Terence O’Neill becomes the fourth Prime Minister of Northern Ireland on March 25, 1963, following the resignation of Basil Brooke, 1st Viscount Brookeborough. He plays a significant role in the first year of the Troubles, trying unsuccessfully to stem growing sectarian violence.

O’Neill is born on September 10, 1914, at 29 Ennismore Gardens, Hyde Park, London, the son of Captain Arthur O’Neill of Shane’s Castle, Randalstown, the first member of parliament (MP) to be killed in action in World War I five months later. He is educated in the English public school system at West Downs School,  Winchester and Eton College, spending his summer holidays at the family estate in Ulster. He is later commissioned in the British Army, rising to the rank of captain and serving with the Irish Guards in World War II. He is wounded in 1944 and opts to resettle permanently in Northern Ireland.

In 1946, O’Neill is elected to the Parliament of Northern Ireland, representing the Unionist stronghold of Bannside. He remains in the parliament at Stormont for almost 25 years. He becomes Northern Ireland’s Minister of Home Affairs in April 1956, Minister of Finance in September 1956 and Prime Minister in March 1963.

As Prime Minister, O’Neill introduces economic reforms to stimulate industrial growth and employment, with mixed results. He also tries narrowing the divide between Protestants and Catholics. He does this with important gestures, like visiting Catholic schools and expressing condolences on the death of Pope John XXIII.

O’Neill also seeks better relations with the Republic of Ireland, and in January 1965 invites Taoiseach Seán Lemass to Belfast. Catholics and moderate Unionists welcome this reconciliation but many conservative Loyalists, like Ian Paisley, condemn it as treachery.

When the civil rights movement erupts in the late 1960s, O’Neill offers a package of reforms and concessions, including changes to the allocation of housing. These proposals, however, anger staunch Unionists and fail to satisfy many Republicans.

In December 1969, O’Neill appears on Northern Ireland television and makes an impassioned plea for unity, warning that “Ulster stands at the crossroads.” His government is reelected in February 1969, though O’Neill himself is almost voted out of his own seat.

With the situation worsening, O’Neill is further embarrassed by Loyalist attempts to sabotage Belfast’s water supply. Fast losing the confidence of his own party, he resigns the prime ministership in April 1969. He remains in the parliament until January 1970.

O’Neill is made Baron O’Neill of the Maine and spends the last decade of his life in Britain’s House of Lords. He dies of cancer on June 12, 1990.