The same credit cannot be given to another phase of his policy, which arose from his relations with Louis, the son of his former rival, the Emperor Louis of Bavaria. The causes of this quarrel must be shortly told. John, the brother of Charles, had married Margaretha Maultasche, Countess of Tyrol; and he had thereby acquired her lands. Margaretha, who seems to have been as foul in mind as she was ugly in face, made a false charge of impotency against her husband; and, under this excuse, she hastened to welcome the advances of young Louis, the son of the Emperor, who helped her to drive her husband from the Tyrol.
The Emperor recognised a so-called marriage between his son and Margaretha; and this act contributed not a little to the storm of indignation which drove the Bavarian from the throne of the Empire and raised Charles to his place. Charles was scarcely seated on the throne, before he resolved to revenge his brother by a raid on the Tyrol. The raid produced no results but bloodshed and misery; and John was forced to console himself for the loss of his lands by the Margravate of Moravia, and for the loss of Margaretha by marriage with a more faithful wife.
But the quarrel between Charles and Louis was not yet at an end. On the extinction of the line of the former Margraves of Brandenburg, the territory had been granted to Louis by his father, and he had remained in undisturbed possession of it for several years. Suddenly, in 1348, a claimant came forward to the Margravate. This man declared that his name was Waldemar; that he was son of the late Margrave of Brandenburg; that, since 1319, he had been supposed to be dead; that his death had been really pretended, in order to escape from a marriage, which, after its celebration, he had found to be illegal; and lastly that, his wife being now dead, he had come forward to claim his inheritance. The story was sufficiently absurd; and it might have been thought that, even if it were true, a prince who had pretended to be dead for nearly thirty years, might, in the interest of peace, consent to pretend a little longer. Charles’s excuse for crediting the imposture was that, as he was too young to remember the real Waldemar, he trusted in the evidence of the Duke of Saxony and other princes of the Empire, who, after investigating the case, declared their belief in the genuineness of the claim. Encouraged by this evidence, Charles only too gladly seized the opportunity for avenging his brother. He declared war on Louis, removed him from his Margravate, and established Waldemar in his place. Eventually it was proved that the so-called Waldemar was the subject and tool of the Duke of Saxony; and Charles, convinced of the imposture, was forced to reinstate Louis in Brandenburg. But, his attention once fixed on this province, he saw in it a new opportunity for aggrandising his House and Kingdom; and, in restoring it to Louis, he secured to his own son Wenceslaus the succession to the Margravate.