Ulster unionism is the belief that Northern Ireland should remain in union with the United Kingdom rather than joining the rest of Ireland. Ulster unionism is a belief prevalent among the Protestant Ulster Scots and the Anglo-Irish, the descendants of the Scottish and English settlers who moved to Ireland during the 17th century. Ulster unionism is the political rival of Irish republicanism, a belief that advocates the unification of Ireland under a single republic and an end to the British occupation of the northern six counties of Ireland. Ulster unionism is represented in Northern Irish politics by the Democratic Unionist Party and the Ulster Unionist Party, the former of which gave its patronage to Ulster paramilitaries such as the Ulster Volunteer Force and the Ulster Defense Association during "The Troubles".