Soon after the peace Vauban accompanied the minister Louvois on a mission to the Duke of Savoy, and furnished plans for the fortifications of Verrue, Verceil, and the citadel of Turin. Returning to Flanders, the works of Dunkerque were prosecuted under his immediate direction with unexampled activity. Three corps of 10,000 men relieved each other daily, every four hours, proceeding from the camp with their arms, and resuming them on the completion of their task. In the midst of these labours he prepared his first work on the attack of fortresses, for the instruction of Louvois, pointing out in it many of the errors committed in former sieges, and proposing remedies for them.
The war with Holland, which commenced in 1672, afforded Vauban many opportunities of displaying his superior abilities. Louis again took the field in person; and again Vauban had the principal direction of the sieges of which the king was a spectator. Previous to the siege of Maestricht, in 1673, the regular method of assaulting a fortified place was to excavate a trench parallel to the general contour of the fortress, and from batteries erected near it to fire indiscriminately on the works and the town. On this occasion Vauban introduced three parallel trenches, connected by oblique or zigzag approaches, which enabled him to place large bodies of infantry near the head of his attack, each successive parallel more closely shutting in the garrison, and restraining their offensive operations.
In 1674 Vauban was promoted to the rank of Brigadier. In the following year he had the magnanimity to second with his recommendation the ineffectual application made by his rival, Coehorn, for employment by the French government.
In 1676 Vauban’s services were rewarded with the rank of Major-General; and in 1677 the mode of attack adopted at Maestricht was perfected at Valenciennes, where the fronts attacked were completely shut in by the parallels, the flanks of which rested on the Scheldt and the marsh of Bourlin.
At this siege it was determined to assault an earthen crown-work, and Vauban proposed to make the attack during the day. Five Marshals of France, Louvois, Monsieur, and even the king himself, opposed this advice. Vauban was immoveable; he maintained that it was the only way to avoid confusion and mistakes, to surprise the enemy, and to overpower him by opposing fresh troops to his wearied garrison. “Night,” said he, “has no shame! Open day and the eye of the commander restrain the cowardly, animate the feeble, and add fresh courage to the brave.” The king at length yielded to his arguments. The enemy was found, as he had predicted, harassed with watching, sleeping, or absent in the fortress seeking provisions. The crown-work, and a ravelin which served as an interior intrenchment, were successively carried. The enemy, retreating into the Paté, an extensive irregular work covering the place, was promptly pursued. Four grenadiers got possession of a sally port, while others entered by a subterraneous passage. The besieged fled into the body of the place, and raised the bridge. An immediate and vigorous assault soon placed the disputed works in the possession of the assailants, who, pushing forward to the canal which traverses the city, intrenched themselves in the houses bordering it. They were strongly and speedily supported, and thus the place was taken at a single assault, justifying Vauban’s advice, even beyond his most sanguine expectations. His services on this occasion were rewarded with a gratuity of 25,000 crowns.
Cambray was besieged next. The town surrendered after a few nights of open trenches. The citadel was then attacked. Du Metz proposed assaulting the ravelin: Vauban opposed this counsel, representing that the strength of the work, and the vigour of the defence, prescribed an attack en règle. “Sire,” said he to the king, “you will lose some one who is of more value than the ravelin.” The success at Valenciennes inspired the troops with temerity: assault was given, the ravelin was carried, and a lodgment in it was commenced; but the enemy brought a heavy fire to bear on the work and its approaches, and then sallying forth speedily drove back the assailants. Du Metz reproached Parisot, the engineer who traced the lodgment, with having caused the failure of the attack. Vauban however insisted that the work was lost, not through any vice in the lodgment, but because the assault could not be sufficiently supported. The siege was then proceeded with in the ordinary manner, and the ravelin secured with the loss of five men only. “I will believe you another time,” said the king to Vauban, and he kept his word. A practicable breach being made, Louis expressed his intention of giving no quarter to the three thousand men who formed the garrison, and had so vigorously defended themselves. Vauban alone ventured to oppose his views, representing that such conduct was contrary to the usages of warfare among civilized nations; that the place would be taken, but would cost more bloodshed; and, “Sire,” he added, “I would rather have preserved 100 soldiers to your majesty than have deprived the enemy of 3000.”
Vauban succeeded to the Chevalier de Clerville, as Commissary-General of the Fortifications of France, in December, 1677. In 1678 he received the congratulations of Colbert on the success attending the execution of his projects for the improvement of the Port of Dunkerque, which, having been previously used only by fishermen, was now made accessible to vessels carrying forty guns. It would be useless to reckon all the labours of this part of his life: the fortifications of Maubeuge, Thionville, Sarre-Louis, Phalzbourg, Béfort, and the citadel of Strasburg, were among the new works projected by him, while all the principal ports and fortifications of France were more or less improved by his master-hand.
The war of 1683 contributed to the increase of Vauban’s reputation. The siege of Luxemburg, in 1684, was carried on under his direction; and he here displayed an admirable presence of mind when discovered one evening by the enemy, in reconnoitring the works of the place. He instantly made a signal to them not to fire, and, instead of retreating, advanced towards them; they mistook him for one of their own officers, and having skirted the glacis, he retired slowly without exciting further suspicion. After having surmounted the many difficulties presented by the nature of the ground over which the attack was necessarily carried, the assailants attained the covered way. To drive the enemy out of its long branches, Vauban caused elevated parapets to be constructed on their prolongations, whence a plunging musketry-fire was thrown into the covered way, and the mass of its defenders were compelled to retreat; the few who remained concealed behind the traverses being gradually dislodged, as the crowning of the covered way was extended along the crest of the glacis. This siege was remarkable both for the difficulties which were overcome, and for the improvements made in the method of conducting an attack and protecting the troops employed in it.
The new fortresses of Mont-Royal, Landau, and Fort Louis, together with extensive projects for the improvement of the canal of Languedoc, formed part of Vauban’s labours during the truce of Ratisbon. He likewise prepared a general project for the improvement and defence of all the ports, roadsteads, and coasts of France. To his exertions the French are indebted for the first general statistical account of their country, he having caused blank forms to be prepared and printed, which he distributed, to be filled up by the several intendants, governors, and other public functionaries with whom his frequent journeys through the country in the execution of his ordinary duties brought him acquainted. Louis XIV. afterwards caused these returns to be made generally throughout France.
The war of 1688 commenced with the siege of Philisbourg, where the Dauphin commanded in person, and Vauban directed the attacks. He here tried the effect of firing en ricochet, of which he was the original proposer. The superiority of this method of attack was not so decisively shown in this first instance as on subsequent occasions: still it proved so far effectual in subduing the fire of the town, as to cause its surrender after twenty-four days of open trenches. The Duc de Montausier said in a letter to the Dauphin, “I do not offer you my congratulation on the fall of Philisbourg: you had a good army, mortars, guns, and Vauban.” On the same occasion, Louis XIV. wrote thus to the successful engineer:—“You know, long since, in what estimation I hold you, and the confidence I have both in your knowledge and affection. Believe that I do not forget the services you render me, and that I am particularly pleased with your conduct at Philisbourg. If you reciprocate the feelings of my son you must be on the best of terms, for I feel assured that he, equally with myself, knows how to esteem and value you. I cannot conclude without earnestly recommending you to preserve yourself for the benefit of my service.”