The terrors of the king’s irresistible strength, and the near prospect of his vengeance, had also compelled George, Landgrave of Hesse Darmstadt, to a timely submission.  His connection with the Emperor, and his indifference to the Protestant cause, were no secret to the king, but he was satisfied with laughing at so impotent an enemy.  As the Landgrave knew his own strength and the political situation of Germany so little as to offer himself as mediator between the contending parties, Gustavus used jestingly to call him the peacemaker.  He was frequently heard to say, when at play he was winning from the Landgrave, “that the money afforded double satisfaction, as it was Imperial coin.”  To his affinity with the Elector of Saxony, whom Gustavus had cause to treat with forbearance, the Landgrave was indebted for the favorable terms he obtained from the king, who contented himself with the surrender of his fortress of Ruesselheim and his promise of observing a strict neutrality during the war.  The Counts of Westerwald and Wetterau also visited the king in Frankfort, to offer him their assistance against the Spaniards, and to conclude an alliance, which was afterward of great service to him.  The town of Frankfort itself had reason to rejoice at the presence of this monarch, who took their commerce under his protection, and by the most effectual measures restored the fairs, which had been greatly interrupted by the war.

The Swedish army was now reinforced by ten thousand Hessians, which the Landgrave of Casse commanded.  Gustavus Adolphus had already invested Koenigstein; Kostheim and Floersheim surrendered after a short siege; he was in command of the Main; and transports were preparing with all speed at Hoechst to carry his troops across the Rhine.  These preparations filled the Elector of Mentz, Anselm Casimir, with consternation; and he no longer doubted but that the storm of war would next fall upon him.  As a partisan of the Emperor, and one of the most active members of the League, he could expect no better treatment than his confederates, the Bishops of Wuertzburg and Bamberg, had already experienced.  The situation of his territories upon the Rhine made it necessary for the enemy to secure them, while their fertility afforded an irresistible temptation to a necessitous army.  Miscalculating his own strength and that of his adversaries, the Elector flattered himself that he was able to repel force by force, and weary out the valor of the Swedes by the strength of his fortresses.  He ordered the fortifications of his capital to be repaired with all diligence, provided it with every necessary for sustaining a long siege, and received into the town a garrison of 2,000 Spaniards, under Don Philip de Sylva.  To prevent the approach of the Swedish transports, he endeavored to close the mouth of the Main by driving piles and sinking large heaps of stones and vessels.  He himself, however, accompanied by the Bishop of Worms, and carrying