Why do Ireland play as one team for Rugby but two teams for Football ?
From 1874 to 1879 there were two Unions for rugby in Ireland. The Irish Football Union had jurisdiction over Clubs in it Leinster, Munster and parts of Ulster; the Northern Football Union of Ireland controlled the Belfast area. The first International was played against England in February 1875. In 1879 the two Unions agreed to amalgamate on the following terms: (i) A Union to be known as the Irish Rugby Football Union was to be formed for the whole country. (ii) Branches were to be formed in Leinster, Munster and Ulster. (iii) The Union was to be run by a Council of eighteen, made up of six from each province. However, with reference to soccer, the FAI was not founded until the 1920’s, by which time Ireland was already split. We didn’t play our first international soccer game until 1924, the Olympics. This is just my guess. maybe others will have a better explanation. The GAA, founded before partition also remains as one body for the whole island.