While the armies of Charles had thus been engaged in winning Italy from his Christian rival, Vienna seemed likely to fall into the hands of the infidel. In May, 1529, Solyman the Magnificent had allied himself with the Hospodar of Moldavia, and with John Zapolya, Waivode of Transylvania, the inveterate enemy of the Hapsburgs, and had invaded Hungary. His pretensions knew no bounds. ‘As there is but one God in Heaven, so must there be but one lord on earth, and Solyman is that lord,’ he proudly asserted, a boast which he hoped to carry into effect by reducing the dominions of the Emperor in Germany. The Austrians, afraid to trust the fidelity of the Hungarian forces, had been unable to meet the Turk, and retreated from the country. Solyman, in possession of the sacred crown of Hungary, which was handed to him by an Hungarian bishop, passed on into Austria, and on the 20th of September laid siege to Vienna. But divided though Germany was, it was not so lost to shame as to allow the Crescent to be established on the walls of the Austrian city. The Reformers, although irritated by their treatment at the hands of the second Diet of Spires (cf. p. 198), answered to the appeal of Ferdinand and to the injunctions of Luther. Vienna was bravely held; and Solyman, threatened by the levies which were coming to its aid, was forced to retreat after a fruitless siege of twenty-four days (October 14). Vienna indeed was saved, but Hungary was held by Zapolya, and Croatia and Bohemia threatened. § 2. _Progress of the Reformation in Germany._ | The Diet of Spires, Aug. 1526, and the Recess.