The combat of Zell (14 September 1796) saw the defeat of a poorly planned Austrian attack on General Moreau's army of the Rhine-and-Moselle just before the start of his retreat across southern Germany in the autumn of 1796.
In the summer of 1796 the French had carried out a two pronged invasion of Germany. Moreau, in command of the southern prong, eventually reached the outskirts of Munich, and was slowly pushing his Austrian opponents back. Further north General Jourdan also advanced a long way into southern Germany, but while Moreau was winning a victory at Friedberg (24 August), Jourdan was suffering a defeat at the hands of the Archduke Charles at Amberg, 80 miles to the north.
Moreau continued to advance until the end of the September, but when the German newspapers reported the news of Amberg he began to slow down. When the news was confirmed Moreau decided that he had to do something to help Jourdan.
Moreau decided to send Desaix, with the entire left wing of his army, to Nuremberg where he hoped it would find Jourdan. On 10 September Desaix crossed the Danube at Neuburg and began a short-lived march to the north. By this point Jourdan was a long way to the west. On 3 September he had suffered a second defeat at Würzburg, sixty miles to the west of Nuremberg, and by 10 September he was approaching Frankfurt am Main. Desaix's march could only end in failure.
Moreau deployed the rest of his army so badly that any competent general could have inflicted a crushing defeat on him. Most of his centre moved to Unterstadt, on the north bank of the Danube close to Neuburg. Delmas was left on the south bank at Zell with six battalions to guard the river crossing. General Ferino, who was dispatched to guard the bridges over the Lech, took up a position at Friedberg, just to the east of Augsburg, between the Rivers Paar and Lech, well over twenty miles to the south west of Neuburg.
Fortunately for Moreau Latour was not a particularly capable general. Faced with a widely spread opponent his first thought always seems to have been to spread himself equally as thin. Instead of focusing all or most of his army against either Ferino or Moreau he decided to send a single division (Mercantin) to attack the French at Neubourg. Froelich was sent to Landsberg, twenty five miles to the south of Augsburg on the Lech. Nauendorf was sent to the north bank of the Danube. Latour himself advanced to Schrobenhausen, just under fifteen miles south of Neuburg and twenty miles north east of Augsburg.
On 14 September Mercantin attacked Delmas's six battalions under cover of fog. Delmas's men came close to breaking. Delmas and Oudinot were both wounded in the fighting, leaving the division without a commander. Moreau placed himself at the head of the division, but if Latour had attacked in real strength the position would have been lost. Instead the French were able to hold on for long enough for Saint-Cyr to send reinforcements from the north bank, and eventually the Austrian attack was fought off.
The Austrians made two more attacks on the French position, both of which ended in failure. The third and final attack ended when the Austrian cavalry broke and fled five miles east to Lichtenau.
Although the French had defeated Latour's attack, Moreau now knew that Jourdan was retreating back to the Rhine. Desaix was ordered to march back to the Danube, crossing back to the south bank on 16 September. Moreau then began a slow retreat back along the Danube, hoping to follow the upper reaches of the river back to the Black Forest and the Rhine. He was even confident enough to pause south of Ulm, where he inflicted a defeat on Latour (battle of Biberach, 2 October 1796), but this gave the Archduke Charles time to move south after forcing Jourdan across the Rhine, and Moreau suffered defeats at Emmendingen (19 October 1796) and Schliengen (23 October 1796) on the western slopes of the Black Forest before crossing back over the Rhine.