In the spring of 1647, the new Prince de Condé was despatched to Catalonia to endeavour to retrieve the reverses sustained in that province, which had of late years earned an unenviable notoriety as the grave of French military reputations. He determined to lay siege to the fortress of Lerida, and, on 18 May, the trenches were opened gaily to the sound of violins. It was a fashion of the time, which made of a war a fête; but it was the hitherto invincible general who had, on this occasion, to pay the expenses of the music; for Lerida was resolutely defended, while the supplies and siege-artillery promised him by the Government did not arrive, and, after severe losses, he decided to raise the siege. Condé deserved credit for having placed the safety of his army before his pride; but it was his first reverse, and, though he was aware that he had done everything possible to ensure success, his mortification was none the less keen. The memory of the Catalonian fiasco was brilliantly effaced in the following year, when, in command of the Army of Flanders, he gained, with comparatively trifling loss, the splendid victory of Lens, over an enemy much superior in numbers, whom, by a feigned retreat, he had succeeded in drawing from an almost unassailable position into a battle on level ground (20 August). This success hastened the conclusion of peace with the Emperor, and, on 24 October, 1648, the Treaty of Westphalia terminated thirty years of war and twelve years of negotiations, and extended the frontiers of France to the coveted line of the Rhine. Left with Spain alone to face, there seemed every reason to hope that a great future awaited France, and that, as the result of two or three successful campaigns, she would be enabled to secure the same advantages in the North-East and South-West as she had already secured in the East. That this hope was only very partially realized, and that not until after more than ten years of further warfare, was due to that miserable internecine strife which, under the name of the Fronde, checked the victorious career of Condé at the age of twenty-seven, plunged France into a welter of anarchy, and sapped the very vitals of the nation.