Far more honourable was his second appearance in the political world. Perceiving that his repeated remonstrances with the Emperor were unavailing, he assembled the archdukes, his brothers and cousins, at Presburg, and consulted with them on the growing perils of their house, when they unanimously assigned to him, as the oldest, the duty of defending that patrimony which a feeble brother was endangering. In his hands they placed all their powers and rights, and vested him with sovereign authority, to act at his discretion for the common good. Matthias immediately opened a communication with the Porte and the Hungarian rebels, and through his skilful management succeeded in saving, by a peace with the Turks, the remainder of Hungary, and by a treaty with the rebels, preserved the claims of Austria to the lost provinces. But Rodolph, as jealous as he had hitherto been careless of his sovereign authority, refused to ratify this treaty, which he regarded as a criminal encroachment on his sovereign rights. He accused the Archduke of keeping up a secret understanding with the enemy, and of cherishing treasonable designs on the crown of Hungary. The activity of Matthias was, in truth, anything but disinterested; the conduct of the Emperor only accelerated the execution of his ambitious views. Secure, from motives of gratitude, of the devotion of the Hungarians, for whom he had so lately obtained the blessings of peace; assured by his agents of the favourable disposition of the nobles, and certain of the support of a large party, even in Austria, he now ventured to assume a bolder attitude, and, sword in hand, to discuss his grievances with the Emperor. The Protestants in Austria and Moravia, long ripe for revolt, and now won over to the Archduke by his promises of toleration, loudly and openly espoused his cause, and their long-menaced alliance with the Hungarian rebels was actually effected. Almost at once a formidable conspiracy was planned and matured against the Emperor. Too late did he resolve to amend his past errors; in vain did he attempt to break up this fatal alliance. Already the whole empire was in arms; Hungary, Austria, and Moravia had done homage to Matthias, who was already on his march to Bohemia to seize the Emperor in his palace, and to cut at once the sinews of his power.