, 1835 On 1 September 1792, Gouvion joined the 1st Battalion of Republican
Chasseurs, a Parisian
volunteer unit from the Quatre-Nations
section. He added his mother's name, Saint-Cyr, to his own to distinguish himself from others. Elected sub-lieutenant due to his education, Gouvion Saint-Cyr became a captain in the 9th Battalion of
fédérés on 1 November, deputy to the adjutant-general of engineers on 1 February 1793, then
chef de bataillon and chief of staff of General
Claude François Ferey. Serving in various staffs in the
Army of the Rhine, Gouvion Saint-Cyr quickly rose through the ranks: he was promoted to brigade general on 5 June 1794 and to general of division on 10 June 1794 by representative on mission
Nicolas Hentz. Gouvion Saint-Cyr commanded the French center at the
Battle of Mainz (1795) under the orders of
Jean-Charles Pichegru and
Jean-Baptiste Kléber. In the
Rhine campaign of 1796, he successfully commanded the left and then the center of the
Army of the Rhine and Moselle under Moreau: he fought at the battles of
Rastatt and
Ettlingen, captured
Stuttgart on 18 July 1796, was victorious at the
Battle of Biberach on October 2, and organized the retreat of the army across the Rhine. Gouvion Saint-Cyr was entrusted with the
defense of Kehl at the end of the campaign, but could not prevent the city's capitulation in January 1797. Gouvion Saint-Cyr temporarily succeeded
Lazare Hoche, who had died at the head of the
Army of the Rhine and Moselle, until
Charles-Pierre Augereau formally took over command. He led the invasion of the
Prince-Bishopric of Basel in December 1797 and occupied it until January 1798. Gouvion Saint-Cyr, who refused to congratulate the
Directory after the
Coup of 18 Fructidor Year V (4 September 1797), then replaced
André Masséna as commander of the Army of Rome from 26 March until 25 July 1798. He restored order and discipline and became unpopular with his soldiers. In addition, Gouvion Saint-Cyr was suspended under charges of abuse of power, which, after investigation, were revealed to be false. He returned to Germany and commanded the left wing under
Jean-Baptiste Jourdan in the
Army of the Danube, took part in the
Battle of Stockach on 25 March 1799, then moved to the
Army of Italy upon Masséna's replacement of Jourdan. Gouvion Saint-Cyr was the commander of the right wing during the defeat at the
Battle of Novi, during which commander-in chief
Barthélémy Catherine Joubert was killed. , 1801 Unwilling to engage in politics, Gouvion Saint-Cyr refused to allow his soldiers to swear an oath to the new
Consulate government, following the
Coup of 18 Brumaire. However, he received from the First Consul,
Napoleon Bonaparte, a sabre decorated with precious stones for his military exploits. He returned to the Army of the Rhine as Moreau's deputy in late 1799. Gouvion Saint-Cyr was received with enthusiasm by the soldiers, and led them to victory at the
Battle of Biberach on 9 May 1800. He was not, however, on good terms with his commander and retired to France after the first operations of the campaign. Gouvion Saint-Cyr was granted leave by Bonaparte and was appointed
State Councillor in the war section.
Stendhal, then Gouvion Saint-Cyr's secretary, described him as "one of the rare military leaders who were capable of studying a dossier". Gouvion Saint-Cyr was tasked with commanding the Franco-Spanish armies during the
War of the Oranges in 1801. When a peace treaty was shortly afterwards concluded with Portugal, he succeeded
Lucien Bonaparte as ambassador at
Madrid. Gouvion Saint-Cyr experienced certain difficulties in this assignment, being more of a soldier than a diplomat. Recalled to Paris in August 1802, he was sent to Italy on 14 May 1803, as lieutenant general of the corps of observation of
Naples under the command of
Joachim Murat. ==Napoleonic Wars==