The Kingdom of Bohemia was one of the wealthiest and strategically important estates of the Habsburgs. During the religious unrest of the 16-17th century, Bohemia was strongly inclined towards Protestantism. The Emperors, remaining strictly Catholic, strongly supported the Counter-Reformation led by the Jesuits, although some religious freedom had to be granted to the reformed confession. The violation of that agreement led to the uprising of the Bohemian Protestants and catalysed the Thirty Years’ War (1618-1648), which raged mainly in German lands to horrifying effect. Gangs of plunderers and marauders destroyed large areas; starvation and epidemics decimated the population. As a result of the war, the country became a hereditary kingdom of the Habsburgs.
Quite expectedly, the Bohemian aristocracy did not welcome the new situation. In the mid-17th century, their reluctance to accept the ascension of Maria Theresa led to the War of Austrian Succession (1740-1748) and the loss of the wealthy province of Silesia. After the war, the Bohemian nobility tried to resist the reform programme initiated by the Empress.