Were the hapsburgs roman catholic or protestant?

The Habsburgs were Roman Catholic but certain sub-groups were greatly influenced by the Reformation. In fact, over "90% of the nobility and a majority of the population" in Lower Austria became Protestants by 1580 (Ehrenpreis, 2006). In Upper and Inner Austria fewer people became Protestants. The division spurred a rebellion from 1618 to 1620 where fighting between the Protestant churches and the largely Catholic government caused casualties and losses on both sides.

Jenni (Librarian-To-Be) #SlamTheBoards

Ehrenpreis, Stefan. (2006). "Karin J. MacHardy, War, Religion and Court Patronage in Habsburg Austria: The Social and Cultural Dimensions of Political Interaction, 1521-1622," The Journal of Modern History 78(1) : 244-246.