The population of the modern nation of Ireland - by which I mean Ireland from the 17th to the 20th century - was comprised not of one, but of of three distinct ethic groups. Each had their own particular history and culture which had always stood in an uneasy coexistence with each other.
By far the largest of these, the native Irish Celts, retained a determined adherence to Catholicism, a faith which for over six centuries had became so intertwined with their culture, that for many, Irishness and Catholicism were often viewed as being one and the same. Even today, when asked to describe a ’typical Irishman’ most people around the world will begin by including ‘Catholic’ in their definition,
The smallest, though perhaps the most talented of the three Irish ethnic groups, were the Anglo-Irish’. Centered mostly around the capital Dublin and in southern Cork, their writers went on to make an outsize contribution to English literature, as did the generals and Field Marshall’s who lead the British Army during the height of Victoria’s Empire, the majority of whom were of Anglo-Irish descent.
Then there were the Scots-Irish, or more accurately, the Ulster-Scots. Strict Presbyterians from lowland Scotland they arrived as part of the great Plantation of Ulster in the 17th C. They were different in many respects from their Anglo Irish counterparts in the south. Firstly, by virtue of their numbers, they quickly became a majority in the province and therefore didn’t feel the same need to accommodate themselves to the native Irish culture as did the less numetous Anglicans in the South. Aggressive and feisty by temperament, they took their religion seriously, which made integration with the local Catholic population more difficult. By the late 19th, and during the fifty years of the 20th C, the Ulster-Scots had transformed their part of Ireland into a center of industry that was not replicated to the same extent in any other part of Ireland. Indeed, a walk through Belfast, with Its factories and rows of red-brick houses, you could easily imagine yourself being in an industrial northern English city.
The proximity of east Ulster to Scotland, and the ongoing social and cultural connections between the Ulster-Scots and their lowland Scots cousins, meant that the former group never became at ease being identified as fully ‘Irish’. It was therefore no surprise when at the time of the partition of Ireland, the most strident group opposing Irish unity, were the Ulster-Scots. When partition became a reality in 1921, the border was defined by the six counties of the historic province of Ulster, where the densest concentration of the descendants from the original Scots immigration to Ulster where to be found.