The Second Defenestration of Prague was a key event leading up to the Thirty Years War. It took place on May 23, 1618, when a group of Protestant rebels threw two Catholic imperial regents and their secretary out of the window of the Bohemian Chancellery. This was a symbolic act of protest against the Catholic Habsburg monarchy and its religious policies in the region. The regents survived the fall, which further infuriated the Protestants. Immediately after the defenestration, the Protestant estates and Catholic Habsburgs started gathering allies for war.