The military career of Vitry did not begin till the breaking out of the war between the protestants and catholics, in 1621. Though he was deficient in principle, he was not so in courage; in the course of the war he distinguished himself upon many occasions, particularly in the isle of Rhé and at the blockade of Rochelle. He obtained the government of Provence in 1631, and he held it for six years. At the expiration of that period, he was arrested, and sent to the Bastile. His having caned an archbishop, and misused his authority in various cases, were among the causes of his imprisonment. Richelieu said of him that, “though his courage and fidelity rendered him worthy to govern Provence, yet it was necessary to deprive him of office, because, being of a haughty and insolent disposition, he was not fit to rule a people so jealous as the Provençals were of their franchises and privileges.” Vitry spent six years in the Bastile, from which prison he was not released till after the death of cardinal Richelieu. During the latter part of his imprisonment he participated in intrigues, which would have brought him to the block had they been discovered. In conjunction with Bassompierre, Cramail, and others, he entered into the plot of which the gallant count de Soissons was the head. The state prisoners in the Bastile were, at that period, allowed so much freedom of intercourse, both with their friends and among themselves, that they had plenty of opportunity to conspire. It was arranged, between Vitry, Bassompierre, and their associates, that, as soon as Soissons had gained a victory, they should seize the Bastile and the Arsenal, and call the citizens of Paris to arms. De Retz is of opinion that the success of their scheme would have been certain; but the death of Soissons, who fell in the battle of Marfée, at the moment of his victory, prevented the conspirators from carrying their design into effect. Fortunately for those who were concerned, their secret practices were never disclosed while cardinal Richelieu was alive. Vitry was created a duke in 1644, but he died in a few months after he obtained this title. He left a son, possessed of talent far superior to his own, and who in character more resembled his grandfather than his father.