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.

Charles V, Emperor of Germany, was at this time the greatest and most powerful sovereign in Europe. He had inherited the kingdoms of Spain, the Netherlands, Naples and Sicily, as well as his possessions in Germany. Born six years later than Solyman, he was elected Emperor of Germany a year before the accession of Solyman as Sultan. He abdicated his throne and retired to a monastery ten years before the death of Solyman. For thirty-six years, therefore, their reigns were synchronous. It would be hard to say which of the two sovereigns was the more valiant in arms, or the more astute statesman. Judged by the extent of conquests, Solyman far surpassed his rival. Charles did little more than maintain the integrity of his immense inherited possessions in Europe. But he acquired by conquest Tunis in Africa, and Mexico and Peru in America.

When Solyman, instigated by Francis I of France, was invading Austria, Charles was deeply engaged in war against France in Italy, and could not send an army to meet the Ottomans in the field. Vienna was left to stand the brunt of invasion without a protecting army. Its garrison consisted of only sixteen thousand soldiers under Count de Salms. Its fortifications were only a continuous wall 5 feet in thickness and without bastions. Its guns were only seventy-two in number. Such weak defences seemed to offer little hope against the overwhelming numbers of the Ottomans. The tents of the Sultan and his army whitened the whole plain round the city. Irregular cavalry, called Scorchers, depending on loot for their food and pay, ravaged the country for miles round the city with incredible cruelty and rapacity. A Turkish flotilla of four hundred small vessels found its way up the Danube, after destroying all bridges, and lent assistance to the siege. It was all in vain. The Austrian and Spanish troops under the Count de Salms defended the weak lines with the utmost courage and tenacity. The Viennese citizens constructed lines of earthworks within the walls, against which the lighter guns of the Turks had little effect. The powerful siege guns of the Ottomans had been left behind en route, owing to heavy rains and the badness of roads. Numerous assaults were made by the Turks. The soldiers were at last dispirited by failure. In vain their officers drove them on by sticks and sabres. The men said they preferred death from their officers to death from the long arquebuses of the Spaniards. Twenty ducats a head were given or promised to them. It was to no purpose. Solyman, after three weeks of fruitless assaults, found himself compelled to raise the siege and to retreat with his great army. His irregulars had so ravaged the country that he had the utmost difficulty in feeding his men.

Before striking the camp all the immense booty taken in the campaign was burnt. The prisoners, most of them the peasantry of the district round Vienna, were massacred. Only the fairest of the young women were carried off captives to be sold as slaves. The Sultan returned to Constantinople. There was no pursuit of his army. It came back intact. It was a slur on the fame of Solyman that he endeavoured to conceal his failure to capture Vienna by lying accounts of success, and by a popular celebration of triumph, on return to his capital. There was this much to be said for him, that he had flouted the Austrians, by invading their country and devastating it up to the walls of Vienna, without any attempt, on their part, to meet him in the field or to follow him up on his retreat.

Three years later, in 1532, Solyman, with another immense army, again invaded Hungary, with the avowed object of marching to Vienna and attacking the army of the Emperor. Charles V, on this occasion, took command of the Austrian army. It was expected that a trial of strength would take place between the two potentates, and would decide which of them was the stronger. But Solyman’s progress was delayed by the heroic defence for three weeks of the small fortress of Guns. After its capture Solyman made no further advance towards Vienna, but turned aside and devastated Styria, and then led his army homeward. The Emperor, on his part, made no effort to meet his foe and join conclusions with him. It was evident that both of them were anxious to avoid the issue of a great battle.

Though the Sultan had retreated and had returned to Constantinople, peace was not concluded, and a desultory war was continued for some years between Ferdinand and Zapolya. Peace was concluded in 1538, under which Zapolya was to retain the title of King of Eastern Hungary and Transylvania and Ferdinand was acknowledged ruler of the western half. In 1566 Solyman again invaded Hungary, on his thirteenth and last campaign, to which we will revert later.

We have thus described briefly the course of events between the Turks and the Hungarians, supported by Austria. Though the conquests of Solyman in this direction had been arrested by his failure to capture Vienna, he succeeded in securing virtual possession of the greater part of Hungary.

It is necessary to revert to Solyman’s feats in other directions. In 1534 he entered upon his sixth campaign, this time against Persia. Shah Ismail was no longer alive, and had been succeeded by Shah Talmasp, a very weak personage. Solyman, as a prelude to his attack, gave orders for the execution of all the Persian prisoners at Gallipoli. Ibrahim was sent on, in advance, by some months, with a large army. Instead of marching by Aleppo to Bagdad, he took the route direct to Tabriz, which he occupied without resistance on the part of the Persians. He wintered there, and the next spring he was joined by Solyman with another army, and together they marched to Mossul and Bagdad, through a most difficult country, where the climate entailed great losses on the army. Bagdad was ultimately reached. It was treacherously surrendered by its commander. In fact, the Shah made no attempt to repel the invasion of the Ottoman army, and the two great provinces of Mossul and Bagdad were added to the Ottoman Empire, without any pitched battle on the part of Persia.

There were other campaigns in Persia in 1548, 1553, and 1554, in which the Turks often suffered more from the climate and from the difficulty of obtaining supplies than from the guerrilla attacks of the Persians. But there was no pitched battle between the armies of the two Powers. The Turks maintained their conquests, and have done so to the present year (1917).