The truce was broken by the Emperor himself. Matthias was an old man without children. His brothers, who were but little younger than himself, were like him childless, and all the hopes of the Austrian House were centred upon Ferdinand of Styria as the only Habsburg who had an heir to succeed him. It became therefore the cardinal point of the policy of the Emperor, during his later years, to secure the succession of Ferdinand to the various dominions of the Austrian House in Germany, and, if possible, his eventual election to the Empire. The succession to the hereditary dominions of the Habsburgs only required the consent of the senior members of the family and the approval of Spain, and presented but little difficulty; but that to the crowns of Hungary and Bohemia was a different matter altogether, as the crown in both kingdoms was elective. By mingled address and assurance the policy of Matthias triumphed for the time. The estates of Hungary duly elected Ferdinand to be the successor of Matthias, and he was crowned at Pressburg without a murmur of opposition being heard. In Bohemia courage won the day. The estates were suddenly called together in 1617, and required to acknowledge Ferdinand as the lawful successor to Matthias by hereditary right, and evidence was brought to show that they had in former times acknowledged that the crown of Bohemia was rightfully hereditary. Taken by surprise and subjected to pressure from the court the estates acquiesced in this new assumption. No leader appeared to question or refute the imperial case. Ferdinand was recognised and crowned as hereditary king of Bohemia, and at his coronation swore to observe the Royal Charter. But no sooner was Ferdinand seated on the throne than the Bohemian Protestant nobility began to realise what had been done. They had not only assisted in placing the most determined enemy of their religion over them, but, by setting aside the elective character of their monarchy, they had dealt the greatest possible blow to their own importance. The discontent found an able leader in count Henry of Thurn, who, like another Christian of Anhalt, was not a man to let scruples stand in the way of his determination to effect the dethronement of Ferdinand, and the overthrow of the House of Austria. [Sidenote: =Revolt of the Protestants in Bohemia. The ‘throwing from the window,’ 1618.=] A meeting of the Protestant members of the estates was summoned, and a petition to the Emperor agreed upon. On the reply proving unfavourable, Thurn, at the head of a body of nobles, forced his way into the palace at Prague on May 23d, 1618, and seizing the two regents of the kingdom, Martinitz and Slavata, who were accused of being the real authors of the obnoxious reply, threw them with their secretary Fabricius out of the window in old Bohemian fashion. They fell sheer seventy feet into the ditch below, but strange to say not one of them lost his life.