Meanwhile the French had crossed the Alps by the Pass of Susa, and occupied Turin (April, 1536). Charles now threw off the mask. He denounced the King as a faithless man, the ally of heretic and infidel, and challenged him to personal combat, suggesting that Burgundy and Milan should be the prize of victory. On this being refused, Antonio de Leyva crossed the Sesia at the head of the imperial troops (May, 1536). The Marquis of Saluzzo, who commanded the French army in Piedmont, deserted to the Emperor, and Charles, neglecting to secure Turin, pressed on into Provence in the hopes of bringing Francis to a decisive engagement. The French, contrary to their usual practice, adopted a Fabian policy. They devastated the country as they retired, and threw themselves into strong positions at Avignon and Valence. Unable to storm these places, the imperial army began to suffer from want and disease, to which de Leyva himself succumbed (September 10, 1536). Charles, despairing of success, was forced to evacuate the country (September 23), and retired to Spain ‘to bury there his honour which he had lost in Provence.’ | Campaigns in Picardy, Languedoc, Artois, and | Piedmont. | Solyman defeats Ferdinand at Essek. Oct. 1537. | Revolt of Ghent, 1537. The attack of the Imperialists on Picardy and Languedoc had been equally unsuccessful, although, during the campaign in Picardy, Francis lost Robert de la Marck, ‘Le Jeune Aventureux,’ the military companion of his youth, and the author of the Memoirs which bear his name. In 1537, the French invaded Artois. The war in Piedmont still continued, and Solyman, in pursuance of his recent treaty, sent Barbarossa to attack the coasts of Naples, while, shortly after, he invaded Hungary in person, and defeated Ferdinand[51] at Essek (October 8). This alliance of the French with Solyman excited the indignation of Europe. Paul III., who had hitherto adopted a neutral attitude, now intervened as mediator. Francis was not unwilling to treat, and Charles had nothing to hope from a continuance of the war. The Lutherans were daily gaining strength; the attack of the Moslem was threatening the imperial hold on Naples; while in the north, the people of Ghent had risen against the taxes imposed by the Regent of the Netherlands (1537). | The Truce of Nice. June 18, 1538.