Charles V. also had to know what necessity was, and to submit to it, without renouncing the totality of his designs. On the 2d of August, 1552, he signed at Passau, with the Protestant princes, the celebrated treaty known under the name of “treaty of public peace,” which referred the great questions of German pacification to a general diet to be assembled in six months, and declared that, pending definitive conciliation, the two religions should be on an equal footing in the empire, that is, that the princes and free towns should have the supreme regulation of religious matters amongst themselves. Charles V. thus recovered full liberty of action in his relations with France, and could no longer think of anything but how to recover the important towns he had lost in Lorraine. Henry II., on the other hand, who was asked by his Protestant allies on what conditions he would accept the peace of Passau, replied that at no price would he dispossess himself of the Three-Bishoprics of Lorraine, and that he would for his part continue the contest he had undertaken for the liberation of Germany. The siege of Metz then became the great question of the day: Charles V. made all his preparations to conduct it on an immense scale, and Henry II. immediately ordered Francis de Guise to go and defend his new conquest at all hazards. [Illustration: DIANA DE POITIERS----243] Ambition which is really great accepts with joy great perils fraught with great opportunities. Guise wrote to Henry II.’s favorite, Diana de Poitiers, Duchess of Valentinois, to thank her for having helped to obtain for him this favor, which was about to bring him “to the emperor’s very beard.” He set out at once, first of all to Toul, where the plague prevailed, and where he wished to hurry on the repair of the ramparts. Money was wanting to pay the working-corps; and he himself advanced the necessary sum. On arriving at Metz on the 17th of August, 1552, he found there only twelve companies of infantry, new levies; and every evening he drilled them himself in front of his quarters. A host of volunteers, great lords, simple gentlemen, and rich and brave burgesses, soon came to him, “eager to aid him in repelling the greatest and most powerful effort ever made by the emperor against their country and their king.” This concourse of warriors, the majority of them well known and several of them distinguished, redoubled the confidence and ardor of the rank and file in the army. We find under the title of _Chanson faite en 1552 par un souldar etant en Metz en garnison_ this couplet:-- “My Lord of Guise is here at home, With many a noble at his side, With the two children of Vendome, With bold Nemours, in all his pride, And Strozzi too, a warrior tried, Who ceases not, by night or day, Around the city-walls to stride, And strengthen Metz in every way.”