As Ferdinand was already the aggressor in Prussia, Gustavus Adolphus thought himself absolved from the usual formalities, and commenced hostilities without any declaration of war. To the other European powers, he justified his conduct in a manifesto, in which he detailed the grounds which had led him to take up arms. Meanwhile he continued his progress in Pomerania, while he saw his army daily increasing. The troops which had fought under Mansfeld, Duke Christian of Brunswick, the King of Denmark, and Wallenstein, came in crowds, both officers and soldiers, to join his victorious standard. At the Imperial court, the invasion of the king of Sweden at first excited far less attention than it merited. The pride of Austria, extravagantly elated by its unheard-of successes, looked down with contempt upon a prince, who, with a handful of men, came from an obscure corner of Europe, and who owed his past successes, as they imagined, entirely to the incapacity of a weak opponent. The depreciatory representation which Wallenstein had artfully given of the Swedish power, increased the Emperor's security; for what had he to fear from an enemy, whom his general undertook to drive with such ease from Germany? Even the rapid progress of Gustavus Adolphus in Pomerania, could not entirely dispel this prejudice, which the mockeries of the courtiers continued to feed. He was called in Vienna the Snow King, whom the cold of the north kept together, but who would infallibly melt as he advanced southward. Even the electors, assembled in Ratisbon, disregarded his representations; and, influenced by an abject complaisance to Ferdinand, refused him even the title of king. But while they mocked him in Ratisbon and Vienna, in Mecklenburg and Pomerania, one strong town after another fell into his hands. Notwithstanding this contempt, the Emperor thought it proper to offer to adjust his differences with Sweden by negociation, and for that purpose sent plenipotentiaries to Denmark. But their instructions showed how little he was in earnest in these proposals, for he still continued to refuse to Gustavus the title of king. He hoped by this means to throw on the king of Sweden the odium of being the aggressor, and thereby to ensure the support of the States of the empire. The conference at Dantzic proved, as might be expected, fruitless, and the animosity of both parties was increased to its utmost by an intemperate correspondence.