The outbreak of the Thirty Years' War followed upon a revolution in Bohemia, which was precipitated by Rudolph's attempt to evade the Royal Charter, extorted from him in 1609 by the estates. Its chief feature was a guarantee of freedom of conscience to Bohemians so long as they adhered to certain recognized creeds; but it also involved questions of authority over lands with respect to their use for religious purposes. The difficulties with the Royal Charter, which had led to Rudolph's downfall in Bohemia, were left to confront Matthias. SAMUEL R. GARDINER Whether it would have been possible in those days for a Catholic king to have kept a Protestant nation in working order we cannot say. At all events Matthias did not give the experiment a fair trial. He did not, indeed, attack the Royal Charter directly on the lands of the aristocracy. But he did his best to undermine it on his own. The Protestants of Braunau, on the lands of the Abbot of Braunau, and the Protestants of Klostergrab, on the lands of the Archbishop of Prague, built churches for themselves, the use of which was prohibited by the abbot and the archbishop. A dispute immediately arose as to the rights of ecclesiastical land-owners, and it was argued on the Protestant side that their lands were technically crown lands, and that they had therefore no right to close the churches. Matthias took the opposite view. On his own estates Matthias found means to evade the charter. He appointed Catholic priests to Protestant churches, and allowed measures to be taken to compel Protestants to attend the Catholic service. Yet for a long time the Protestant nobility kept quiet. Matthias was old and infirm, and when he died they would, as they supposed, have an opportunity of choosing their next king, and it was generally believed that the election would fall upon a Protestant. The only question was whether the Elector Palatine or the Elector of Saxony would be chosen. Suddenly in 1617 the Bohemian Diet was summoned. When the Estates of the kingdom met they were told that it was a mistake to suppose that the crown of Bohemia was elective. Evidence was produced that for some time before the election of Matthias the Estates had acknowledged the throne to be hereditary, and the precedent of Matthias was to be set aside as occurring in revolutionary times. Intimidation was used to assist the argument, and men in the confidence of the court whispered in the ears of those who refused to be convinced that it was to be hoped that they had at least two heads on their shoulders.