Soon after this, the mental condition of the king made it necessary that his duties should be undertaken by a substitute, and his brother William, the prince of Prussia, took his place for three months. In October 1858 the prince became regent. The accession to power of the new regent was universally recognized as involving a change of system. The temper of William, in contradistinction to that of his brother, was pre-eminently practical; and he had the reputation of a brave, piously orthodox Prussian soldier. The nickname "cartridge-prince" (_Kartätschenprinz_) bestowed upon him during the troubles of '48 was undeserved; but he was notoriously opposed to Liberalism and, had he followed his own instincts, he would have modified the constitution in a reactionary sense. Fortunately, however, he was singularly open to conviction, and Otto von Bismarck, though not yet in office, was already in his confidence. Bismarck realized that, in the struggle with Austria which he foresaw, Prussia could only be weakened were she to take up an attitude of opposition to the prevailing Liberal sentiment, and that to tamper with the constitution would not only be inexpedient, but useless, since special measures could always be resorted to, to meet special circumstances. The interests of Prussia, he urged, had been too often sacrificed to abstract ideas. William listened and was convinced. He not only left the constitution intact, but he dismissed Manteuffel's "feudal" ministry and replaced it with moderate Liberals. The change was more revolutionary in appearance than in reality. Manteuffel and his policy were associated in the regent's mind with the humiliation of Olmütz, and the dismissal of the ministry symbolized the reversal of this policy. William believed with his whole soul in the unification of Germany, and in Prussia as its instrument; and, if he doubted, it was only as to the how and when. Of one thing he was certain--that whoever aspired to rule over Germany must be prepared to seize it (letter to von Natzmer, May 20, 1849). This attitude had little in common with the Liberal appeal to the voice of the people. Such a revolutionary foundation might be good enough for the ephemeral empires of France; the appeal of Prussia should be to the God of battles alone. Prussia and the Austro-Italian War.