It is not difficult to conceive the desperation of Frederick William as he learned the ominous disposition made of the lands belonging to his allies. The Elector of Hesse-Cassel had remained ostensibly neutral in the war, having requested and been refused membership in the Rhine Confederation. But he had mustered about twenty thousand men on a war footing: his heir was in the Prussian lines. He was rightly suspected of trimming to both currents: his people loathed and despised him. The day after Jena he was informed that the Emperor had been aware of his secret sympathy with the coalition, and that his feelings had been evidenced by the permission granted the Prussian troops to pass through his domain while his own army was (p.~443) ready for action. This conduct made it necessary to occupy his states. Mortier, the French commander at Mainz, was ordered to seize the prince and imprison him in Metz; on November fourth it was curtly announced that the house of Hesse had ceased to reign. The fact was, the territories of that house were needed for a new subsidiary kingdom, the formation of which had been for some time in contemplation. The Elector of Saxony, whose troops had fought with the Prussians at Jena, was, on the other hand, offered the privilege of neutrality, and, abandoning his former ally, he eagerly accepted. The dukes of Saxe-Gotha and Saxe-Weimar followed his example, and obtained immunity by submission. The Duke of Brunswick had withdrawn to his capital. Thence he appealed to his conqueror for mercy in behalf of his dominions. Napoleon's reply was pitiless, recalling the duke's notorious proclamation of 1792 against the French republic, and declaring that it was he also who had been the real instigator of the present war. The sting of this retort was in its truth and the humbled warrior in mortal agony betook himself to Altona, where he expired. Brunswick, Hanover, Hamburg, and their domains were all occupied by French troops and put under martial law.