That death, however, instead of bringing peace to Wenceslaus, only raised against him a far more formidable opponent. The Emperor Frederick had opposed the efforts of his turbulent namesake; but, when the Duke died without an heir, it seemed an excellent opportunity for seizing Austria as a fief of the Empire. Wenceslaus, on the other hand, desired to secure the dukedom for his son Vladislav; and, in spite of Imperial opposition, he seems to have won for his son the sympathies, of a part, at least, of the Austrian nobles. Thus then ended abruptly that alliance between Bohemia and the Empire which had been so useful to both parties. Neither Wenceslaus nor Frederick lost time in their declarations of hostility to each other. In 1247 Wenceslaus openly joined in the schemes of Innocent IV., for deposing the Emperor, and setting up William of Holland in his place; and Frederick revenged himself by stirring up the discontented Bohemian nobles against their king. The struggle was a sharp one; the rebels succeeded for a time in deposing Wenceslaus and setting up young Ottakar in his stead; but the threats of Innocent IV. brought them back to their allegiance; and a compromise by which young Ottakar was confirmed in his former government of Moravia removed him from the ranks of his father’s enemies. The death of Frederick II. once more plunged the Empire into disorder. Wenceslaus saw his opportunity in this confusion; and, as Vladislav was now dead, the King persuaded young Ottakar to seize the dukedom of Austria for himself. The Austrians accepted their new duke without any apparent reluctance; and thus, when Wenceslaus died in 1253, Ottakar II. became king of a Bohemia, which included not only Silesia and the Lausitz, but also the dukedom of Austria. IV. THE GROWTH OF BOHEMIAN LIFE FROM ACCESSION OF PR̆EMYSL OTTAKAR I. TO DEATH OF PR̆EMYSL OTTAKAR II. (1198-1278.) In the present century the development of national constitutions has had a special interest for historians. This interest has arisen partly from the spectacle of the unusual number of new experiments in government which have been made in our own time; partly from the growing sense that the history of wars and Courts has become less important, and that the growth of law and of popular life ought to take the place of those exploded subjects of interest. But the exact legal position of the different component parts of a nation is not generally easy to ascertain at an early period of its history; nor, when it is ascertained, has the knowledge always brought us nearer to the discovery of the really living and progressive force in the nation at that period.