Conor Cruise O'Brien, who has died aged 91, had an extraordinarily varied career in which he was a diplomat, politician, author, critic, journalist and academic.
Conor Cruise O'Brien was a renaissance man
In almost every field he worked in, he managed to stir up controversy.
Conor Cruise O'Brien was born in Dublin on 3 November 1917, the son of a journalist. Though he was raised a Catholic, he soon rejected religion.
From Trinity College, Dublin he went into the Irish civil service.
In 1944, he transferred to the External Affairs department, and in 1956, after a spell in Paris, became a member of the Irish delegation to the United Nations. His speeches often showed an independence of judgement and an ability to appreciate the Afro-Asian point of view.
In 1961, when the Congo was threatened with civil war over Mr Moise Tshombe's move for a separate Katanga, Dr O'Brien was chosen by the Secretary General, Mr Dag Hammarskjold, as his special representative to the Congo which had become newly independent under Patrice Lumumba.
His brief was essentially a peacekeeping one, but when he announced that the secession of Katanga was at an end there were strong protests from Britain and other Western powers that the UN was exceeding its role and interfering in the Congo's internal politics.
During the row, Mr Hammarskjold arrived in the Congo, but on his way to meet Mr Tshombe in Northern Rhodesia his plane crashed and everyone on board was killed.
Dr O'Brien stayed on in Elisabethville for a time, the centre of increasing controversy. At the end of 1961 he resigned from the UN post and from the Irish Foreign Service.
O'Brien as UN representative in Katanga
He later related how western governments had deliberately destabilised Lumumba's state in his book, To Katanga and Back.
In 1962 Dr Kwame Nkrumah invited Dr O'Brien to become vice-chancellor of the University of Ghana; he left after three years, disillusioned with government corruption.
He went back to America as Albert Schweitzer Professor of Humanities at New York University even though he had once described Schweitzer, a missionary leader, as someone who "embodied the most noxious aspects of the white man in Africa".
In 1969 he stood for parliament in North-East Dublin and won the seat for Labour. He became his party's spokesman on foreign affairs and particularly on the civil unrest in Northern Ireland.
As violence increased, he became recognised as an outspoken and courageous opponent of violence. The IRA was a particular target for him: he condemned it as a fanatical, foreign-hating, intolerant movement.
When the Fine Gael and Labour coalition government was formed in 1973, Mr Liam Cosgrave appointed him Minister for Posts and Telegraphs. As political overseer of the Irish broadcasting service he forbade interviews with IRA representatives.
He was a leading advocate of a more liberal attitude in the Irish Republic on matters such as divorce and contraception. He also called for the Republic's territorial claim over Northern Ireland to be removed from its Constitution.
O'Brien with Marie McEntee en route to Ghana
In the general election of June 1977 the coalition government was defeated and Dr O'Brien lost his seat in the Dail. Two months later he was elected to the Senate.
He became editor-in-chief of the Observer in 1978 and held the post for three years. He resigned in 1981 after it was bought by Lonrho under its chief, Tiny Rowland, whom he felt was not suited to own a newspaper.
O'Brien, however, continued to write for the paper and remained on the board as consultant editor. He had earlier (June 1979) resigned his seat in the Senate of the Republic of Ireland where he had represented the University of Dublin since 1977.
Dr O'Brien had a considerable reputation as a critic and essayist, and several collections of his writings and lectures were published.
The best known of his books on his native country is States of Ireland, published in 1972. Dr O'Brien was twice married. He and his first wife had three children, and after their divorce (in Mexico) in 1962, he married Miss Maire MacEntee, a colleague in the Foreign Service and a daughter of a former deputy prime minister of the Irish Republic.
Old age did not blunt his capacity for controversy. In his 80s, he joined the UK Unionist Party for a time, which opposed the Northern Ireland peace process, dismaying many of his admirers.
However, later he re-joined the Irish Labour Party in 2004. That year, he also ended a long-running dispute with the taxman over some of his earnings over 20 years which he believed should be tax-free under the Artists' Exemption Scheme.