Complex sentence: The GAA's nationalist ethos secured support amongst the Catholic and nationalist community, but also opposition within the Protestant and unionist community.Particularly in relation to Northern Ireland, the sports are played almost exclusively by members of the mainly Catholic nationalist community.
Split into simpler sentences: The GAA's nationalist ethos secured support amongst the Catholic and nationalist community, but also opposition within the Protestant and unionist community. In Northern Ireland, the sports are played almost exclusively by members of the mainly Catholic nationalist community.