When he saw the moment arriving at which he could effectually intervene in the affairs of Germany--a part of which had its eyes directed to France, and was only waiting for a signal from the Louvre to escape from the incessant rivalries of the princes and from religious contentions--he took measures not only to facilitate a successful intervention abroad, but to strengthen his frontiers and establish depôts and centres for provisioning his troops. Assured of the good-will of the Swiss and tranquil as regarded Italy--thanks to the alliances he had formed in that Peninsula--and wishing to act at once in the east, and on the Pyrenean side, he turned his attention to the defences of Roussillon and of the line which unites Burgundy with Champagne. Henry IV. had been engaged in partisan warfare; but then he had only his own life at stake. As a sovereign he thought it his duty not to run risks; and before launching into the great enterprises he had in view, and which might change the face of Europe, he wished to put fortune on his side as far as possible. For more than six years, in concert with Sully, he had lost not a day or an hour in preparing for France, which had been a prey to civil war and invasion at the end of the sixteenth century, a future of the noblest order, and which might have secured to it the most honourable destiny, if the hand of an assassin had not in a single day destroyed hopes founded in a wise policy and the most thoughtful foresight. This prince knew by experience that in war a check is always possible, even when fortune is, or seems to be, entirely on our side, and that the talent of a general consists in his ability to discover new resources after a reverse. Success in arms is secure in proportion to the foresight exercised in preventing a first reverse from becoming a disaster. Henry IV. therefore set about preparing a good line of retreat and supply in the rear of the army, which he was intending to lead in person towards the east. He put in a state of defence the towns and important strategic points from Châlons-sur-Saône, passing through Beaune, Dijon, Langres, along the course of the Haute-Marne, and from Langres to Chaumont, Saint-Dizier, Châlons, Reims, Laon, Péronne, and Amiens. Verdun and Metz had been visited by him, with a view to examining their defences. At Metz he had ordered works of considerable importance. The town of La Roche-Pont was comprised in that portion of this line of defence which lay between Dijon and Langres. The engineer Errard de Bar-le-Duc had been entrusted with these operations, beginning with Châlons-sur-Saône. He had, we may observe, merited the confidence reposed in him by the king, for he had given proofs of considerable ability and ingenuity.