Army of the Danube order of battle The Army of the Danube was a field army of the First French Republic . Originally named the Army of Observation , it was expanded with elements of the Army of Mainz ( Mayence ) and the Army of Helvetia ( Switzerland ) . The army had three divisions , plus an advanced guard , a reserve , and an artillery park . The Army crossed the Rhine River on 1 March 1799 under the command of Jean - Baptiste Jourdan , in the order of battle below . As elements crossed the Rhine , they took the name Army of the Danube . The crossing was completed by 7 March . After passing through the Black Forest , the Army fought two battles in quick succession , the Battle of Ostrach , on 20 – 21 March , and Stockach , on 25 – 26 March . It suffered badly in both engagements and , following the action at Stockach , withdrew to the Black Forest . Jourdan established his headquarters at Hornberg , and the Reserve cavalry and the cavalry of the Advance Guard quartered near Offenburg , where the horses could find better forage . Initially , the Army included five future Marshals of France : its commander - in - chief Jourdan , François Joseph Lefebvre , Jean - Baptiste Drouet , Laurent de Gouvion Saint - Cyr , and Édouard Adolphe Casimir Joseph Mortier . After the defeat at Ostrach , the Army was reorganized and command shifted to another future marshal , André Masséna . Under Masséna ' s command , elements of the army participated in skirmishes in Switzerland , the eleven - hour Battle of Winterthur and the First and Second Battles of Zürich . The Army was disbanded in November 1799 and its units dispersed among other French field armies by mid - December . Staff . Jean - Baptiste Jourdan received command of the Army of Observation in September 1798 , from its temporary commander , Pierre Marie Barthélemy Ferino . From October to December , he assessed its condition . By 27 February 1799 had drawn together his general staff and laid out his operational plan for a Danube campaign . Advance Guard . The Advance Guard crossed the Rhine River at Kehl , and marched to the northeast . François Joseph Lefebvre was indisposed — suffering from ringworm — and Jourdan had appointed General of Division Dominique Vandamme to direct the march . Vandamme had been lobbying with Jourdan for a larger and more important command but , given the claims of other officers , this was the best Jourdan could do for him . Vandamme led the Advance Guard through the mountains via Freudenstadt . On 5 March , Lefebvre returned to his command . Within a week , part of the advanced guard broke off from the main body and , under command of Vandamme , moved to Stuttgart , to investigate the rumored presence of Habsburg units . I . Division . The Division crossed the Rhine River at Hüningen near Basel , Switzerland , and marched in two columns eastward . The right column , commanded by Jean Victor Tharreau , moved along the northern shoreline of the Rhine . The left column , commanded by Jean - Baptiste Jacopin , moved at the northern - most rim of the river valley . From Switzerland , Masséna sent a Demi - brigade of the Army of Helvetia to secure Schaffhausen , part of the Swiss cantons that lie north of the Rhine river . In holding Schaffhausen , Masséna insured the passage of Ferino ' s forward units . Ferino ' s orders were to proceed from Schaffhausen along the north shore of Lake Constance , also called the " Bodensee " . His left flank was to remain in contact with the II . Division , to prevent the Austrians from piercing the army ' s forward line . His advance units were to proceed as far as the Imperial Abbey of Salem . From there , he was instructed to prevent any Austrian reinforcements from Switzerland joining with Archduke Charles , whom Jourdan expected to move across the Iller river near Augsburg , and advance into Swabia . II . Division . The Division followed the Advance Guard across the Rhine , also at Kehl . As it approached the mountains , II . Division followed the river valleys east of Freudenstadt . At the Battle of Ostrach , II . Division took position behind François Joseph Lefebvre ' s Advance Guard , on the slope below Pfullendorf . At the Battle of Stockach , Souham ' s Division , positioned in the center , was to coordinate a simultaneous assault with Ferino ' s I . Division on the Austrian left flank . III . Division . The Third Division and the Reserve also crossed at Kehl , and then divided into two columns , III . Division traveling through the Black Forest via Oberkirch , and the Reserve , with most of the artillery park , via the valleys at Freiburg im Breisgau , where the horses would find more forage , and then over the mountains past the Titisee to Loffingen and Hüfingen . At the Battle of Ostrach , after more than 15 hours of general engagement , the Austrians flanked the III . Division ' s left wing and pressed the entire Division back to the Pfullendorf heights . At the Battle of Stockach , Saint - Cyr and Vandamme were to execute simultaneous attacks on the Austrian right flank , Saint - Cyr on the front and Vandamme from the rear ; the attacks failed when Archduke Charles moved support troops from the left flank . Reserve . The Reserve crossed the river at Kehl , swung south toward Freiburg im Breisgau , and crossed the mountains at Neustadt , to Loffingen , Bruhlingen and Hüfingen . At the Battle of Ostrach , the Reserve remained in the northern outskirts of Pfullendorf and did not participate in the battle except in small groups . When Jourdan decided to withdraw , d ' Hautpoul ' s cavalry moved to the west first , to secure bridges and the east - west roads . At the battle of Stockach , the Reserve was slow to support of Ferino ' s I . Division , which had run out of ammunition ; when a cavalry charged failed to materialize , the Austrians acquired the upper hand . Jourdan later charged d ' Hautpoul with dereliction . After the Stockach engagement , most of the Reserve withdrew to the west side of the Black Forest , where the horses could find forage , but by late April , the Reserve had joined with the André Masséna ' s Army of Helvetia outside of Zürich ; d ' Hautpoul joined them in July after he was cleared by a Courts - martial in Strasbourg . Artillery park . Command : Jean Ambroise Baston de Lariboisière