Henry IV. seized the opportunity. He at once declared himself the protector of the rights of the elector of Brandenburg and the count of Neuburg, and put himself at the head of an alliance of the enemies of the Austro-Spanish House. England, the United Provinces, the German Protestant Union, Venice and Savoy responded to his call. Three French armies were set on foot, one was directed to the Pyrenees, the second under Lesdiguières was to co-operate with Savoy and Venice in the conquest of the Milanese, while the third, under the command of the king himself, attacked Jülich and occupied the duchies in conjunction with the Dutch and English contingents and the German Protestants. It seemed as if the death-knell of the Austro-Spanish power had sounded. Rudolf II., ignorant of politics and half-crazed in intellect, was implicated in serious quarrels with his unwilling subjects of Bohemia and Hungary. In Styria, Carinthia, and Carniola, Ferdinand, the nephew of the Emperor, was, with the help of the Jesuits, waging an ardent and determined war against the Calvinism which threatened to take a strong root even in the hereditary dominions of the Habsburgs. Wanting in money, wanting in leadership, wanting in unity, the power of Austria had no troops on which it could depend, no subjects which it could trust. Nor was Spain in much better plight. Exhausted by the ambition of Philip II., misgoverned by a weak king and an incapable minister, she had chosen this very time gratuitously to deal a serious blow to her own prosperity by expelling from her borders the Moriscoes, the most laborious and intelligent of her working population. It was clear that she could do little more to help the cause than to defend her own frontiers, and hold the Milanese against the attacks of the allies. The forces of the Catholic League, the resources of Maximilian of Bavaria, and the genius of his general Tilly, were in fact all that Catholicism and the Austro-Spanish power had to rely upon in the death duel in which she had almost by inadvertence engaged herself. [Sidenote: =Assassination of Henry IV.=] Help came from a quarter the least expected. A terrible crime struck France with tragic suddenness to her knees and saved the House of Austria. As Henry IV. passed through the streets of Paris to visit his minister Sully, but two days before the date fixed for his departure for the campaign, a fanatic named Ravaillac plunged a dagger into his heart. With Henry IV. died the combination of which he was the head and soul, and the capture of Jülich from the imperialists by Maurice of Nassau, aided by a small English contingent, was the only step taken in the direction of realising the Great Design of the first of the Bourbons. [Sidenote: =Marie de Medicis declared Regent.=]