Two nations theory (Ireland)
In Ireland, the two nations theory proposes that there are two peoples on the island with national rights to self-determination: an Irish nation substantially formed by the Roman Catholic majority; and, concentrated in the north-east (in parts of Ulster), a Protestant community of Scottish and English descent which is insistent on a continued union with Great Britain. Emerging in the 19th century as a response to the drive for Irish self-government, variants of the theory gained renewed currency from the late 1960s when the onset of Northern Ireland Troubles called the 1921 partition settlement into question.
Source: Wikipedia — Two nations theory (Ireland) (CC BY-SA 4.0)