During the peace of Ryswick, Vauban made a tour of the northern frontiers, in which he was occupied three years, preparing projects for canals and various other public works, as well as for the improvement of existing and the construction of new fortresses; among others, of Neuf-Brisach, his last work, in which he improved on his system of tower bastions, previously applied at Béfort and Landau. In 1699 he was elected an honorary member of the French Academy; and, January 2, 1703, was promoted to the rank of Marshal of France; a dignity which he modestly wished to decline, lest it might, at a future period, deprive him of the opportunity of serving his country. In the autumn of 1703 Vieux-Brisach was besieged by the army under the orders of the Duc de Bourgogne, who is reported to have thus addressed Vauban:—“Monsieur Maréchal, you must lose your honour before this place: for either we shall take it, and if so, they will say you have fortified it badly; or we shall fail, and they will then say that you have ill assisted me.” “Monseigneur,” replied Vauban, “it is already known how I have fortified Brisach; they have yet to learn how you will take the places I have fortified.” The siege lasted only thirteen days, and was the last at which Vauban served. The following year he presented to the Duc de Bourgogne his treatise on the Attack of Fortresses, first published at the Hague by Pierre Dehoult, in 1737. When Turin was attacked, in 1706, M. de la Feuillade rejected the project of attack submitted by Vauban, and the result was, that a perfect investment was not completed until after three months’ fighting. Louis XIV., annoyed at the duration of the siege, and at the progress of Prince Eugene, sent for Vauban, who, after pointing out the faults of the attack, offered to give his assistance as a volunteer. “Recollect,” said the king, “that this employment is beneath your dignity.” “Sire,” replied Vauban, “my dignity consists in serving my country. I will leave my baton at the door, and perhaps may assist M. de la Feuillade in taking the city.” La Feuillade refused the proffered aid, lest he should have to share with Vauban the honour of taking Turin: an honour, however, which he did not acquire, being forced to raise the siege after ninety-seven days of open trenches.