Franz von Lauer Franz von Lauer ( 11 May 1736 – 11 September 1803 ) began his service in the Austrian army as an engineer officer and became a general officer while fighting against Ottoman Turkey . He earned recognition as a siege specialist while fighting the armies of the First French Republic during the French Revolutionary Wars . He served as Chief of staff of the army fighting against Napoleon Bonaparte in Italy in 1796 . Appointed as deputy commander of the army in southern Germany , his efforts ended in a military disaster in December 1800 . Early career . Born in 1736 , Lauer studied at the Engineer Academy and joined the army of Habsburg Austria army in 1755 . After being promoted to Captain during the Seven Years War , he became an expert in siege warfare . He received promotion to Major in 1773 , Oberstleutnant in 1779 , and Oberst in 1783 . During the Austro - Turkish War ( 1787 - 1791 ) he earned appointment to the rank of General - Major and the Knight ' s Cross of the Military Order of Maria Theresa for his distinguished actions at the Siege of Belgrade in 1789 . He was appointed the noble rank of Freiherr in 1790 . War of the First Coalition . Lauer fought on the upper Rhine River under the command of Dagobert Sigmund von Wurmser in 1793 - 1794 . On 13 October 1793 , Wurmser ' s army defeated the French in the First Battle of Wissembourg . Putting his engineering talents to good use , Lauer conducted a successful siege of Fort - Louis beginning the day after the battle . On 14 November , he accepted the surrender of the 4 , 500 - man French garrison and fortress , which was then situated on an island in the Rhine River . Still with Wurmser , he fought at the successful siege of Mannheim in late 1795 . For notable actions in capturing a redoubt on 30 October , he earned the Commander ' s Cross of the Military Order of Maria Theresa . Promotion to Feldmarschallleutnant followed on 4 March 1796 . Lauer performed repairs to the fortifications of Mantua when the siege of that city was briefly raised in early August 1796 . On 19 August an order arrived from Emperor Francis II insisting that Wurmser attempt the second relief of the Siege of Mantua . The same order nominated Lauer as Wurmser ' s chief - of - staff . When drawing up the plan of attack , Lauer assumed that losses would prevent the French from quickly reacting to an Austrian offensive . This belief proved to be a mistake when Bonaparte hurled three divisions north into the upper Adige River valley . After overwhelming Paul Davidovich ' s covering force at the Battle of Rovereto , the French general sent his troops marching east , then south down the Brenta River valley . Bonaparte crushed Wurmser at the Battle of Bassano on 8 September , then followed the Austrian when he raced southwest toward Mantua . Ultimately , Wurmser became trapped in Mantua with nearly 30 , 000 soldiers . " To his credit , Lauer thereafter proved the key man during the very stubborn defense of Mantua . " The fortress finally surrendered on 2 February 1797 . After the War of the First Coalition Lauer became the Director - General of Engineers , a post that he held from April 1797 to February 1801 . War of the Second Coalition . When hostilities broke out in 1799 in the War of the Second Coalition , Lauer was recalled to the field . Jean Moreau ' s victories over Pál Kray ' s Austrian army in May through July 1800 resulted in an armistice on 15 July . During this time , the Austrians were driven from the Rhine to the Inn River . The emperor decided to replace Kray with the 18 year old Archduke John of Austria . Appointed Feldzeugmeister on 5 September , Lauer became John ' s second - in - command . The emperor expected John to remain a figurehead while Lauer made the important decisions , creating a very awkward command structure . In September , Lauer pleaded for an extension of the truce and was upheld by the emperor . The old general hoped that his army could gain strength for the inevitable clash . On 12 November the armistice lapsed and war broke out again . Franz von Weyrother , Archduke John ' s chief - of - staff , persuaded John and Lauer to adopt an offensive strategy against the French . Because of the limitations of the Austrian army , the hard marching only succeeded in tiring out the troops for the coming battle . The combination of John ' s inexperience , Weyrother ' s aggression , and Lauer ' s inability to restrain his colleagues proved fatal . The Austrians scored a costly victory over the French at the Battle of Ampfing on 1 December 1800 . This success made the archduke and his staff reckless in their zeal to get to grips with Moreau . Lauer remained cautious but found himself unable to impose his views on the army headquarters . On 3 December , the Austrians advanced in four non - mutually supporting columns through rough terrain to open the Battle of Hohenlinden . Moreau ' s army ambushed the Austrians and enveloped their left flank , inflicting a decisive defeat . After a vigorous French pursuit , the Austrian army ' s morale collapsed , and the emperor was forced to sue for peace . Blamed for the disaster , Lauer retired from the army in 1801 . He died in Krems , in modern - day Austria on 11 September 1803 . He married Maria d ' Allio and his son Joseph Lauer , born in 1769 , also became a general .