The advances of Philip, though he declined to do anything prejudicial to the Protestant cause, were welcomed by the Emperor. Following Bucer's advice, the landgrave now proceeded to take active steps with the hope of establishing religious peace between the Roman Catholics and Protestants. Secure of the imperial favor, he agreed to appear at the Diet of Regensburg in 1541, and his presence there contributed to the direction affairs took at the Regensburg religious colloquy, in which Melanchthon, Bucer, and Johann Pistorius the Elder represented the Protestant side. Philip was successful in securing the permission of the Emperor to establish a university at Marburg, and in return for the concession of an amnesty, he agreed to stand by Charles against all his enemies, excepting Protestantism and the Schmalkaldic League; to make no alliances with France, England, or the duke of Cleves; and to prevent the admission of these powers into the Schmalkaldic League.