To a deputation from the Austrian Estates he was firm and unbending. They might threaten as they pleased, but the confederation with Bohemia he would not sign. Rougher and rougher grew the menaces addressed to him. Some one, it is said, talked of dethroning him and of educating his children in the Protestant religion. Suddenly the blare of a trumpet was heard in the court below. A regiment of horses had slipped in through a gate unguarded by Thurn, and had hurried to Ferdinand's defence. The deputation, lately so imperious, slunk away, glad enough to escape punishment. [Sidenote: § 5. The siege raised.] Little would so slight a reinforcement have availed if Thurn had been capable of assaulting the city. But, unprovided with stores of food or siege munitions, he had counted on treason within. Disappointed of his prey, he returned to Bohemia, to find that Bucquoi had broken out of Budweis, and had inflicted a serious defeat on Mansfeld. [Sidenote: § 6. The Imperial election.] Ferdinand did not linger at Vienna to dispute his rights with his Austrian subjects. The election of a new Emperor was to take place at Frankfort, and it was of importance to him to be on the spot. To the German Protestants the transfer of the Imperial crown to his head could not be a matter of indifference. If he succeeded, as there seemed every probability of his succeeding, in re-establishing his authority over Bohemia, he would weigh with a far heavier weight than Matthias upon the disputes by which Germany was distracted. The Elector Palatine and his councillors had a thousand schemes for getting rid of him, without fixing upon any. John George of Saxony, in 1619 as in 1612, had a definite plan to propose. Ferdinand, he said, was not in possession of Bohemia, and could not, therefore, vote as King of Bohemia at the election. The election must, therefore, be postponed till the Bohemian question had been settled by mediation. If only the three Protestant electors could have been brought to agree to this course, an immediate choice of Ferdinand would have been impossible. [Sidenote: § 7. Ferdinand chosen Emperor.] Whatever might be the merits of the proposal itself, it had the inestimable advantage of embarking the Lutherans of the North and the Calvinists of the South in a common cause. But Frederick distrusted John George, and preferred another plan of his own. John George lost his temper, and voted unconditionally for Ferdinand. Frederick, if he did not mean to be left alone in impotent isolation, had nothing for it but to follow his example. He had no other candidate seriously to propose; and on August 28, 1619, Ferdinand was chosen by a unanimous vote. He was now known as the Emperor Ferdinand II. [Sidenote: § 8. Frederick elected King of Bohemia.] Two days before, another election had taken place at Prague. The Bohemians, after deposing Ferdinand from the throne, which in 1617 they had acknowledged to be his, chose Frederick to fill the vacant seat.