François , marquis de Chasseloup - Laubat François , marquis de Chasseloup - Laubat ( August 18 , 1754 – October 3 , 1833 ) , French general and military engineer , was born at Saint - Sernin ( Charente Inferieure ) , of a noble family , and entered the French engineers in 1774 . He was still a subaltern at the outbreak of the Revolution , becoming captain in 1791 . His ability as a military engineer was recognized in the campaigns of 1792 and 1793 . In the following year he won distinction in various actions and was promoted successively " chef de bataillon " and colonel . He was chief of engineers at the siege of Mainz in 1793 , after which he was sent to Italy . He there commanded the positions and lines of advance of the army of Bonaparte . He was promoted brigadier - general before the close of the campaign , and was subsequently employed in fortifying the new Rhine frontier of France . His work as chief of engineers in the army of Italy ( 1799 ) was conspicuously successful , and after the battle of Novi he was made general of division . When Napoleon took the field in 1800 to retrieve the disasters of 1799 , he again selected Chasseloup as his engineer general . During the peace of 1801 - 1805 he was chiefly employed in reconstructing the defences of northern Italy , and in particular the afterwards famous Quadrilateral . His " chef - d ' œuvre " was the great fortress of Alessandria on the Tanaro . In 1805 he remained in Italy with André Masséna , but at the end of 1806 Napoleon , then engaged in the Polish campaign , called him to the Grande Armée , with which he served in the campaign of 1806 - 07 , directing the sieges of Colberg , Danzig and Stralsund . During the Napoleonic domination in Germany , Chasseloup reconstructed many fortresses , in particular Magdeburg . In the campaign of 1809 he again served in Italy . In 1810 Napoleon made him a councillor of state . His last campaign was that of 1812 in Russia . He retired from active service soon afterwards , though in 1814 he was occasionally engaged in the inspection and construction of fortifications . Louis XVIII made him a peer of France and a knight of St Louis . He refused to join Napoleon in the Hundred Days , but after the second Restoration he voted in the chamber of peers against the condemnation of Marshal Ney . In politics he belonged to the constitutional party . The king created him a marquis . Chasseloup ' s later years were employed chiefly in putting in order his manuscripts , a task which he had to abandon owing to the failure of his sight . His only published work was ' ( Paris , 1801 , republished Milan , 1805 and 1811 , under the title ' ) . The most important of his papers are in manuscript in the Depot of Fortifications , Paris . As an engineer Chasseloup was an adherent , though of advanced views , of the old bastioned system perfected by Vauban . He followed in many respects the engineer H . J . B . de Bousmard , whose " Essai General de Fortification " was published in 1797 and who fell , as a Prussian officer , in the defence of Danzig in 1807 against Chasseloup ' s own attack . His front as applied to Alessandria , contains many elaborations of the bastion trace , with , in particular , masked flanks in the " tenaille " , which served as extra flanks of the bastions . The bastion itself was carefully and minutely retrenched . The ordinary " ravelin " he replaced by a heavy casemated " " after the example of Montalembert , and , like Bousmard ' s , his own ravelin was a large and powerful work pushed out beyond the " glacis " . His wife , the daughter of François Fresneau de La Gataudière , brought him the Château de la Gataudière , at Marennes , Charente - Maritime ; his youngest son , Prosper de Chasseloup - Laubat , was Minister of the Navy under Napoleon III .