If his troops were few in number, it is not to be denied that they were excellent in quality. Many were hardened veterans from the king's earlier campaigns; among his recently acquired mercenaries there was a Scotch brigade, from which he drew many of his best officers. We hear much during the following years, of Hepburn, Seaton, Leslie, Mackay, and Monroe, whose names betray their Caledonian origin. You would have supposed now that the Protestant princes, having secured the aid of Gustavus, would have made haste to identify themselves with his cause and to reinforce him with money and troops. But, strange to relate, no sooner had he landed than they began to grow afraid of him and to ask themselves whether they might not after all, be able to make more tolerable terms with the emperor by the sacrifice of their religion, than with this foreign invader, who, if he was victorious, might dictate his own terms. Had they not, in other words, jumped from the frying-pan into the fire? The two princes who had hitherto been the most prominent champions of Protestantism in Germany (though both half-hearted and pusillanimous shufflers) were Gustavus's brother-in-law, the Elector of Brandenburg, and the Elector of Saxony. They were now doing their best to wriggle out of their obligations, and by a shameful neutrality avert the emperor's displeasure. But they had reckoned without their host if they supposed that Gustavus would lend himself to such a scheme. The reply which he gave to Herr von Wilmerstorff, who had been sent to him by the Elector to urge an armistice, was refreshingly plain, while the argument which accompanied it was completely unanswerable. When nevertheless the Elector continued to resort to shilly-shallying and all sorts of ambiguous tactics, Gustavus lost his patience, marched his army to the gates of Berlin, and compelled him to make his choice of party once, for all. The treaty of alliance was then signed, on the Elector's part reluctantly and with a heavy heart; for these two brothers-in-law were so vastly different, that it was scarcely to be expected that they would be congenial. Gustavus, though he was not without personal ambition, was fired with noble zeal for the Protestant cause, and believed it worthy of any sacrifice, however great; while the Elector was only bent on saving his own precious skin and extricating himself with the least possible damage from the dangerous situation in which he had been caught. [Illustration: Gustavus Adolphus before the battle of Lutzen.]