Nor was it difficult to give a national colouring to the class selfishness of the nobles. It will be remembered that Ottakar II. had introduced a large German element into the towns which he had founded. This measure of wise policy had been changed into a means of cruel oppression by Otto of Brandenburg; and, unfortunately for the cause of the towns, Otto had been, apparently, the first ruler who summoned their representatives to share in the deliberations of the Estates of the Realm. Moreover, Henry of Lipa added to his class prejudices a more personal reason for opposing the existing government. He was attached to the widow of the late King Rudolf, who was known to her supporters as the Queen of Grätz; and he was resolved to make good both her claims and his own at the expense of the peace and order of the country. To the unscrupulous intriguers who were plotting against their power, John and the Archbishop of Mainz were unfortunately soon to supply some just causes of complaint. The death of the Emperor Henry seemed to open to John a chance for claiming the Imperial throne; and, when he found that his youth was held to disqualify him for that dignity, he threw all his influence on to the side of Louis of Bavaria, as he was resolved that no Hapsburg, at any rate, should again become Holy Roman Emperor. This contest withdrew both him and the Archbishop from Bohemia; and the German Councillors who were left to support the queen were little able to stand against Henry of Lipa. John soon found that his championship of the Bavarian cause was likely to involve him in a dangerous war; and, fearing to leave a disturbed Bohemia behind him, he hastened to satisfy his opponents by dismissing his German advisers and taking Henry of Lipa into his counsels. A new Hungarian war which broke out at this time enabled Henry to increase his power, and he used it for inflicting new oppressions on the Bohemian towns. But a bolder act of presumption at last exhausted the patience of the Court. Henry ventured, without consulting king or queen, to grant Agnes, the queen’s sister, in marriage to a Duke of Silesia. This insolence at last roused John to action, and Lipa was arrested. Before any further steps could be taken, John was once more called to the German war; and he again left the Archbishop of Mainz as his viceroy. Henry of Lipa once more appealed to Bohemian feeling against the German prelate; and, though many of the better men among the Bohemian nobility were now disposed to stand by their queen, they were not strong enough to hold their own against these intrigues. John was now earnestly entreated to return to Bohemia; but, when he hastened back, at the head of his Rhenish forces, his Bohemian advisers urged him to leave the Germans behind, and to throw himself on the support of his faithful nobles. John rejected this advice; he re-entered Bohemia at the head of his German troops, and proceeded to attack the lands of those nobles who had resisted him.