Although several incidents are said to have contributed to the 30 years war, the event that sparked the conflict the order of Archbishop of Prague to have protestant church be destroyed. The people appealed to Emperor Matthias, who ignored their protests. The protestants started to revolt. The events that has been marked the beginning of the war is known as the Defenestration of prague, in which the people punished officials by throwing them out of windows. The civil war in Bohemia spread thoughout Europe. The death of Emperor Matthias emboldened the rebellious Protestant leaders, eliminating the possibility of a peace treaty. The weaknesses of both Ferdinand and of the Bohemians led to the spread of the war to western Germany. Ferdinand was forced to call on his nephew, King Philip of Spain, for assistance. The Bohemians desperately applied to be admitted into the Protestant Union to gain allies in their war. The Bohemians hinted at making Frederick the King of Bohemia if he allowed them to join the Union and come under its protection. However , this attempt failed due to interception of the letters, and other simiaThis unraveled much of the support for the Bohemians, particularly in the court of Saxony. The rebellion initially favoured the Bohemians. They were joined in the revolt by much of Upper Austria, whose nobility was then chiefly Lutheran and Calvinist. Lower Austria revolted soon after, and in 1619, Count Thern led an army to the walls of Vienna itself.