Spain. [Sidenote: The troubles in Bohemia.] The failure of Ralegh came at a critical moment in German history. In 1617, while he was traversing the Southern seas, Ferdinand was presented by Matthias to the Diet of Bohemia, and acknowledged by it as successor to that kingdom. As had been foreseen, he at once began the course of forcible suppression of Protestantism which had been successful in his other dominions. But the Bohemian nobles were not men to give up their faith without a fight for it; and in May 1618 they rose in revolt, flung Ferdinand's deputies out of the window of the palace at Prague, and called the country to arms. The long-dreaded crisis had come for Germany; but, as if with a foresight of the awful sufferings that the struggle was to bring, the Germans strove to look on it as a local revolt. The Lutheran princes longed only "to put the fire out"; the Calvinistic Union refused aid to the Bohemians; the Catholic League remained motionless. What partly accounted for the inaction of the Protestants was the ability of the Bohemians to hold their own. They were a match for all Ferdinand's efforts; through autumn and winter they held him easily at bay. In the spring of 1619 they even marched upon Vienna and all but surprised their enemy within his capital. But at this juncture the death of Matthias changed the face of affairs. Ferdinand became master of the whole Austrian heritage in Germany, and he offered himself as candidate for the vacant Imperial crown. Union among the Protestants might have hindered his accession, and with it the terrible strife which he was to bring upon the Empire. But an insane quarrel between Lutherans and Calvinists paralyzed their efforts; and in August 1619 Ferdinand became Emperor. Bohemia knew that its strength was insufficient to check a foe such as this; and two days before his formal election to the Empire its nobles declared the realm vacant, and chose Frederick, the young Elector-Palatine, as their king. [Sidenote: Outbreak of the Thirty Years War.]