"Irish nationalist/republicans (mainly Roman Catholic) and unionist/loyalist (mainly Protestant).""
And both of those represent he two religions
Stop taking things about of context again
The Unionists declared a Protestant State and the Catholics became second rate citizens - inferior voting rights and propertty ownership was the meing cause of contention.
The Troubles started when Catholics demanded equal rights
For Christ#s sake Keith - http://www.historyireland.com/18th-19th-century-history/the-men-of-no-popery-the-origins-of-the-orange-order/
Jim Carroll