In that same year 1632 a still nobler head was to fall. The story of Henry de Montmorency’s ruin tangles itself with the treasonable adventures of Gaston d’Orléans. Duke Charles of Lorraine, nominally a vassal of the Empire, had reasons of his own for giving trouble to France. For nearly a century she had held part of the old province of Lorraine, including the “Three Bishoprics,” Metz, Toul, and Verdun. In giving armed support to the exiled French prince, Charles IV. had the Empire at his back, and a successful invasion of France, with the consequent fall of Cardinal de Richelieu, was likely not only to restore his territory but to be a decisive incident in the Thirty Years’ War. At this moment of happy expectation, Monsieur fell in love with the young Princess Marguerite of Lorraine, the Duke’s sister. A year or two before he had been desperately in love with Princess Marie de Gonzague, daughter of the Duke of Mantua, and the Queen-mother had imprisoned her at Vincennes to be out of his way. This was a more serious affair. A secret, hurried marriage at Nancy united Gaston to the one woman who kept her hold on him through the rest of his frivolous life. But even before the marriage, the Duke of Lorraine’s plans of conquest had fallen through. French armies had crossed his frontier, driving before them the small force which the Emperor had sent to his aid. From the stronghold of Metz, Louis XIII. and Cardinal de Richelieu were able to dictate their own terms. The Duke of Lorraine was to become a faithful ally of France, and all her enemies were to be expelled from his territory. In consequence of this treaty, Monsieur joined his mother at Brussels. Left to himself, he might have been reconciled with the King, and Richelieu did his best to that end; but his own friends and favourites found it to their interest to keep him in rebellion. It was not till after the signature of the treaty that Louis XIII. was made aware of his brother’s marriage, to which he had definitely refused his consent. In this and other ways the Duke of Lorraine had played Richelieu false. The consequence was that a French army once more swept over the province, seizing towns and fortresses and bringing Richelieu’s favourite dream--that of extending the French frontier to the Rhine--perceptibly nearer. At this moment, having taught the Duke a second severe lesson, Richelieu held his hand. The victories of Gustavus Adolphus in Germany were an effectual check on the house of Hapsburg, and hindered the advance of the Spanish and Imperial troops on the Rhine. A French army was needed at home. Monsieur had left Brussels with a small army of German, Walloon, and Spanish mercenaries, and had made a dash through Lorraine, Burgundy, and Auvergne on his way to Languedoc, with the encouragement of the Duc de Montmorency. Leaving Maréchal d’Effiat in command on the German frontier, Richelieu despatched Schomberg and La Force by different routes to the south.