Rudolf II was succeeded in 1612 by his brother, the Emperor Matthias who sought to install the fiercely Catholic Ferdinand of Styria on the Bohemian throne (which was conjoined with that of the March of Moravia), but in 1618 the Protestant Bohemian and Moravian noblemen, who feared losing religious freedom (two of the Protestant churches being already forcibly closed), started the Bohemian Revolt. The Revolt was defeated in 1620 in the Battle of White Mountain. As consequence the local Protestant noblemen were either executed or expelled from the country while the Habsburgs put Catholic (and mostly German speaking) nobility into their place. The Czech language was gradually reduced to a means of communication between peasants, who were often illiterate. The era is generally described as the "Dark Age of the Czech Nation".