the son of the eldest surviving daughter), was almost alone in opposing Rudolf. Other candidates were Prince Siegfried I of Anhalt and Margrave Frederick I of Meissen (1257–1323), a young grandson of the excommunicated Emperor Frederick II, who did not yet even have a principality of his own as his father was still alive. By the admission of Duke Henry XIII of Lower Bavaria instead of the King of Bohemia as the seventh Elector, Rudolf gained all seven votes. King of the Germans Rudolf was crowned in Aachen Cathedral on 24 October 1273. To win the approbation of the Pope, Rudolf renounced all imperial rights in Rome, the papal territory, and Sicily, and promised to lead a new crusade by taking the crusader's vow in 1275. Pope Gregory X, despite the protests of Ottokar II of Bohemia, not only recognised Rudolf himself, but persuaded King Alfonso X of Castile (another grandson of Philip of Swabia), who had been chosen German (anti-)king in 1257 as the successor to Count William II of Holland, to do the same. Thus, Rudolf surpassed the two heirs of the Hohenstaufen dynasty whom he had earlier served so loyally. In November 1274, the Imperial Diet at Nuremberg decided that all Crown estates seized since the death of the Emperor Frederick II must be restored, and that King Ottokar II must answer to the Diet for not recognising the new king. Ottokar refused to appear or to restore the duchies of Austria, Styria and Carinthia together with the March of Carniola, which he had claimed through his first wife, a Babenberg heiress, and which he had seized while disputing them with another Babenberg heir, Margrave Hermann VI of Baden. Rudolf refused to accept Ottokar's succession to the Babenberg patrimony, declaring that the provinces reverted to the Imperial crown due to the lack of male-line heirs. King Ottokar was placed under the imperial ban; and in June 1276 war was declared against him. Having persuaded Ottokar's former ally Duke Henry XIII of Lower Bavaria to switch sides, Rudolf compelled the Bohemian king to cede the four provinces to the control of the royal administration in November 1276. Rudolf then re-invested Ottokar with the Kingdom of Bohemia, betrothed one of his daughters to Ottokar's son Wenceslaus II, and made a triumphal entry into Vienna. Ottokar, however, raised questions about the execution of the treaty, and procured the support of