Gustavus Adolphus suddenly appeared before Stettin. Pomerania, like Brandenburg, had been devastated by the Imperialists. Bogislav Fourteenth, Duke of Pomerania, yielded to the inevitable and made a treaty with Gustavus Adolphus, whose army at the close of the year 1630 had been increased to thirty thousand men by accessions from Sweden and by deserters from the enemy. At the beginning of the year 1631 a treaty was made between Sweden and France, for the increasing power of the Emperor had long displeased France. In Germany about this time the Duke of Saxe-Weimar, the Landgrave Ludwig Wilhelm of Hesse-Cassel, and the city of Magdeburg declared for Gustavus Adolphus. The Imperialists retreated before him. He attacked Frankfort and took the city by storm. Not a single combatant was spared, because Tilly, at the capture of Neubrandenburg, had killed two thousand Swedes in violation of the rules of warfare. Gustavus Adolphus next appeared before Berlin and ordered the Elector to declare whether he would close a treaty with him, like the princes named above, or be his enemy. The Swedish party in Berlin, to which the Electoress and her mother belonged, besides most of the councillors (among them Pruckmann and Von Burgsdorf, whose acquaintance we have made at Letzlingen) exerted themselves to the utmost to induce the Elector to make the treaty; but it came to nought. Gustavus Adolphus meanwhile received word from Magdeburg that it was besieged by Tilly, and that it depended upon him to relieve the city. But this master of war knew that in spite of all calculations and the utmost courage a retreat might be necessary if he did not occupy strong positions, so as not to be cut off from his base of operations. Gustavus Adolphus desired the concession of the fortresses of Spandau and Cüstrin. The Elector consented, but upon condition that the fortresses should be given back immediately after the raising of the siege. Gustavus Adolphus now advanced toward the Elbe, sent ambassadors to the Elector of Saxony, and asked of him the surrender of Wittenberg that he might have free passage of the Elbe. The Elector hesitated while the danger to Magdeburg steadily increased. Suddenly came the dreadful news that Magdeburg had fallen. Of its thirty-five thousand citizens, thirty thousand were put to death by Tilly’s hordes, and after a few days in the place of a flourishing city only a heap of ruins was left, from which the smoke of the fires which had been kindled rose to heaven. The news of the fall of Magdeburg deeply pained the King, but his courage did not waver in the least. Chapter XVII In a Garden House at Berlin