The Defenestration of Prague is an incident of Bohemian resistance to the Hapsburg authority that was central to the start of the Thirty Years War. It happened on May 23, 1618. In response to Roman Catholic officials in Bohemia closing Protestant chapels, an assembly of Protestants tried and found guilty the imperial regents of violating the Letter of Majesty. They then threw the men and their secretary out the window.
The imperial regents William Slavata and Jarolsav Martinic and the secretary Fabricius were not seriously injured after being thrown from the windows of the council room of Prague Castle. The act signaled the beginning of a Bohemian revolt against the Hapburg emperor Ferdinand II, which was one of the opening phases of the Thirty Years War. The Letter of Majesty was made by Emperor Rudolf II in 1609 to guarantee certain religious freedoms. In 1617, by closing Protestant chapels that were being built by the citizens of the towns Broumov and Hrob, the Roman Catholic officials violated the Letter of Majesty. The assembly of Protestants was appointed under the Letter of Majesty to safeguard Protestant rights.
The word "defenestration" refers to the act of throwing someone out a window. Another Defenestration of Prague occurred in 1419, but the term usually refers to the later incident. The first incident occurred when a mob of radical Czech Hussites killed several members of the city council and was a turning point that lead to the Hussite Wars.