The combat of Langenbruck (1 September 1796) was an unsuccessful Austrian counterattack that came close to the end of General Moreau's successful advance into southern Germany in the summer of 1796. In the aftermath of the battle of Neresheim (11 August 1796) the Archduke Charles decided to leave the Austrian army on the Danube and join the army facing General Jourdan. General Latour was left in command on the Danube, with orders to prevent General Moreau from advancing north to join Jourdan. Latour's early efforts were not successful, and on 24 August the French crossed the River Lech (battle of Friedberg) and forced him to retreat towards Munich.
Latour took up a new position along the Iser. His left was close to Munich, and his right was at Landshut, 30 miles down the river. Latour had strong forces guarding all of the bridges over the river, and he also had a bridgehead on the south bank of the Danube at Ingolstadt, well to the west of his main line.
Moreau decided that he couldn't attack across the Iser while both of his flanks were potentially vulnerable to counterattack. He couldn't do much about the threat to the right, from the Tyrol, but the bridgehead at Ingolstadt could be eliminated. In late August Moreau advanced slowly towards the Iser and prepared to attack Ingolstadt.
Moreau advanced on a wide front. Laborde was on the extreme right, and by 1 September had reached Kempten, close to Munich. Ferino was at Dachau, to the north-west of Munich. Saint-Cyr was in the centre of the French line, at Freising and Pfaffehofen (roughly half way between Munich and Ingolstadt). Desaix was at Geisenfeld (ten miles to the south east of Ingolstadt) and Guntersried (another of many unidentifiable locations in early French sources). The attack on Ingolstadt was to be carried out by Delmas.
By the end of August Latour knew that the Archduke Charles had defeated General Jourdan at Amberg (24 August 1796), and had even received reinforcements under General Nauendorf.
The fighting took place in a triangular area on the western banks of the River Ilm, a minor tributary of the Danube. The northern tip of the triangle was at Geisenfeld, on the Ilm. The western tip of the triangle was at Langenbruck, on the main road to Ingolstadt. The third corner of the triangle was on the Ilm to the south east of Langenbruck. When the fighting began the French had troops posted at Geisenfeld and at St. Kastl (just to the south west of Langenbruck).
Encouraged by the arrival of his reinforcements Latour decided to mount a cavalry attack on the French positions in the angle between the Iser and the Danube. The first shock fell on the 10th demi-brigade of light infantry at Geisenfeld. They were forced to fall back to the south-west, but managed to delay the Austrian cavalry for long enough for the French reserves to reach St. Kastl. The Austrians then captured this position, and forced Desaix to pull back to some woods behind Gambach.
The next Austrian target was Langenbruck. The village itself was soon captured, but the French held a position on some hills above the village. By now the Austrian cavalry had been joined by some infantry, which made two attempts to capture this ridge, both times attacking in columns and both times being repulsed.
After this failure the Austrians sent 4,000 cavalry into the gap between Langenbruck and Geisenfeld, with the intention of heading west to outflank the French left. In order to carry out this plan the Austrians had to cross a swampy area close to the river and then climb up onto a ridge of higher ground to the west. Desaix noticed the Austrian movement, and was able to move strong force into place on that ridge without the Austrians noticing (one battalion from the 62nd of the line, the 8th Chasseurs, 6th Dragoons, 1st Carabineers and a company of light artillery).
The Austrian cavalry reached within twenty-five paces of the top of the ridge when the Carabineers revealed themselves by opening fire. The Austrians were forced back down into the march, where they were attacked in the flanks by the Chasseurs and Dragoons. This forced them to retreat in front of the line infantry, who also opened fire. The Austrians were forced to retreat after suffering heavy loses.
Desaix was now strong enough to go onto the offensive. A battalion of the 97th demi-brigade forced the Austrians out of St. Kastl, and the Austrians retreated back to the north-east, escaping via Geisenfeld.
Latour had a lucky escape from a more serious defeat. Saint-Cyr, who was attacking Freising, could have advanced north east and cut off the Austrian retreat, but the direction of the wind meant that he never heard the guns from Geisenfeld.
Moreau made one more attacking move. On 3 September the French moved up the Iser. By the end of the day they held Freising, Moosburg and a bridge over the river, and Moreau was planning to attack Munich, but news now began to reach him of Jourdan's defeat at Amburg on 24 August. After waiting for a few days to make sure the news was accurate, Moreau was forced to begin his own retreat back towards the Rhine.