The election of Count Zapolya as King of Hungary under the dictation of the Turks led to civil war in that country. Archduke Ferdinand, brother of Charles V, to whom the Emperor had transferred his Archduchy of Austria, claimed the throne of Hungary, by virtue of a treaty between the Emperor and the late King Louis. On the other hand, it was claimed by Zapolya and his adherents that, under an ancient law of Hungary, no one but a native could be elected as King. In spite of this, the nobles of Western Hungary met in Diet at Presburg and elected Ferdinand. Ferdinand appealed to arms, and was supported by the Austrians. He defeated his rival. Zapolya was driven from the country. He fled to Poland, and thence he appealed to the Sultan for aid in support of his claims in Hungary. Ferdinand, hearing of this, sent an envoy to the Sultan. Most unwisely, he not only claimed assistance in support of his claims to the throne of Hungary, but he demanded that Belgrade and other towns in Hungary in possession of the Sultan should be given up. Ibrahim, the Grand Vizier, who conducted the negotiations with the two rivals, was most arrogant. He claimed that every place where the hoofs of the Sultan’s horses had once trod became at once and for ever part of the Ottoman Empire. “We have slain,” he said, “King Louis of Hungary. His kingdom is now ours to hold or to give to whom we list. It is not the crown that makes the King, it is the sword. It is the sword that brings men into subjection; and what the sword has won the sword will keep.” The Sultan decided against Ferdinand and said to Zapolya’s envoy, “I will be a true friend to thy master. I will march in person to aid him. I swear it by our Prophet Mahomet, the beloved of God, and by my sabre.” To the rival’s agent he said that he would speedily visit Ferdinand and drive him from the kingdom he had stolen. “Tell him that I will look for him on the field of Mohacz or even in Buda, and if he fail to meet me there, I will offer him battle beneath the walls of Vienna.” In pursuance of these threats, Solyman, in 1529, at the head of two hundred and fifty thousand men and with three hundred guns, again invaded Hungary and laid siege to Buda. The city surrendered at the instance of traitors among its defenders. Under the terms of capitulation life and property were to be preserved to the garrison and the citizens. The Janissaries, furious at the loss of loot, refused to recognize the terms. They massacred all the garrison as they issued from the fortress, and they carried off for sale most of the young women of the town. Zapolya was reinstated as a vassal King of that part of Hungary. Solyman then marched on to Vienna. He arrived there on September 27, 1529, with over two hundred thousand men. There ensued the first of the two memorable sieges of Vienna by the Ottomans.