The former Taoiseach, Dr Garrett FitzGerald, has said the IRA campaign brought Dublin and London closer together than any two governments in Europe.
The IRA unwittingly created a "normalisation of Irish-British relations" that pre-Troubles observers would not have believed possible. Since 1972, both governments had effectively agreed on peace and stability in Northern Ireland as their main objective, he said.
They concurred that until a majority in the North decided otherwise, the state would remain within the UK. Dr FitzGerald was speaking at the weekend in Belfast at an Irish Association seminar, "Ancestral Shadows".
Other speakers at the seminar included Ms Una O'Higgins-O'Malley, whose father, Kevin O'Higgins, the Minister for Home Affairs, was assassinated in 1927, and Ms Maire MacSwiney Brugha, whose father, Terence MacSwiney, Lord Mayor of Cork, died on hunger-strike in 1920.
Mr Ruairi Brugha, whose father, Cathal, a leading anti-treatyite, was killed in the Civil War, and Mr Joseph McCull ough, whose father, Denis, was a Cumann na nGaedheal TD, also took part.
Dr FitzGerald said his mother, Mabel McConnell, initially disagreed with her husband, Desmond FitzGerald, the Minister for External Affairs, over the treaty.
His mother's correspondence showed she wanted the new government "thrown out as soon as possible". However, the assassination of Mr Kevin O'Higgins and the government's performance had changed her sympathies by 1927.
Ms O'Higgins-O'Malley said she often tried to imagine "my father's views of his years from 1916-27 and how he would relate them to the present situation in Ireland".
She continued: "If I understand him, it is as one facing daily on-the-ground realities, determined to deal with the here-and-now and not with what might have been . . . someone who understood more than most the extent the sacrifices the South would have to make if the Border were to be removed and the dream of a united Ireland were to be realised."
Her father understood the "reality of the North" more than any other Southern politician for perhaps the next 50 years. He believed there had to be some gains for unionists in any settlement and he developed the idea of a dual monarchy.
Ms O'Higgins-O'Malley said she was "struck by the regard" many unionists had for his memory. Even the Rev Ian Paisley had "quoted him with approval" in the British House of Commons.
Ms Maire MacSwiney Brugha said her father's hunger-strike had an enormous impact in "India, Africa, America, the Far East and all over the world". Everyone "knew of Terence MacSwiney and of the Irish struggle".
Mr Ruairi Brugha said growing up in a republican house and attending protest parades as a child in the post-Civil War years had been exciting. He explained his own decision to join Clann na Poblachta and later Fianna Fail.