For most of the first forty years of their existence, the two Irish states, born from the partition settlement of 1921, luxuriated in the celebration of their distinctive communal identities. Political leaders on both sides of the border exchanged increasingly hackneyed expressions of Irish nationalist aspiration to abolish the 'British-imposed' partition of the island and Ulster unionist reiteration of their determination to defend their British national identity from the nationalist challenge. In contrast, the period 1959-65 has been seen by some influential commentators as one in which the philosophies and political priorities of both states in Ireland were transformed. The rose-tinted terms in which the period has come to be seen are clear from the following description taken from Conor Cruise O'Brien's recently-published Ancestral Voices. O'Brien argues that this was a time when 'Irish politics seemed to be moving in a quite different direction: a time in which political leaders in the Republic seriously sought accommodation with unionist leaders, and were prepared, and equipped to resist the Catholic-nationalist territorial drive.'1 The two figures at the centre of this potentially historic shift were Sean Lemass, who had succeeded De Valera as leader of Fianna Fail and Taoiseach in 1959, and Terence O'Neill, who replaced Lord Brookeborough as Prime Minister of Northern Ireland in 1963. Like many commentators, O'Brien depicts both Lemass and O'Neill as modernisers. He describes O'Neill as having 'tried to fight the powerful sectarian element in Ulster Unionism, and to end discrimination against Catholics'.2 Sean Lemass is portrayed as having tried to meet O'Neill half way by attempts to 'normalize' relations between nationalists and unionists on the island of Ireland. The high point of detente came in 1965 when Lemass went to Belfast to meet O'Neill, an occasion summed up by O'Brien as 'the first meeting of the leaders of the two communities on the island, since the foundation of the two political entities within it in 1920-21'. He argues that: 'Basically the understanding between them was that Northern Ireland would begin to end discrimination against Catholics, and that the Republic would cease to challenge the legitimacy of Northern Ireland.'3