The combat of Heidelberg (25 September 1795) was an Austrian victory that ended any chance that the French could take advantage of the unexpected surrender of Mannheim five days earlier.
1795 had been a quiet year on the Rhine, but in September the French launched a two-pronged offensive. General Jourdan crossed the Rhine north of Mainz, while General Pichegru was meant to cross further south. Rather than crossing the river, Pichegru then advanced north, and on 20 September he summoned Mannheim to surrender. Much to his surprise the city surrendered at the first summons, giving Pichegru an invaluable foothold across the Rhine.
The capture of Mannheim exposed the main Austrian supply depot at Heidelberg to attack. The city was defended by a small force under General Quosdanovich. The main Austrian army under General Clerfayt was too far north to save the city, as was a new Austrian army forming under General Würmser. If Pichegru had moved east in strength he could easily have captured the city, and forced Clerfayt to retreat to the east to secure his supplies.
Pichegru failed to take advantage of this opportunity. On 23 September two divisions were sent towards Heidelberg, and even this small force was split in two. General Dufour's 7th Division advanced along the right back of the Necker, and General Ambert's 6th Division along the left bank.
Quosdanovich concentrated most of his troops on the right bank. On 23-24 September the French were able to push them back, but on 25 September Quosdanovich realised how small the French force and attacked Dufour with all the forces at his disposal. The isolated French division was routed. Dufour was killed, and his division lost 1,200 men killed or wounded. Many of the survivors reached safety by crossing a ford to join the 6th Division.
Quosdanovich's victory removed the threat to Heidelberg. The surviving French troops retreated to Mannheim, while Pichegru remained inactive. Würmser's new army soon reached the front line, allowing Clerfayt to concentrate against Jourdan, and in mid-October he was forced to retreat back across the Rhine.