The affair of Gruningen of 21 April 1797 was a minor incident during the Austrian retreat after their defeat at Neuwied on 18 April that is remembered because during it General Ney was captured by the Austrians. Having originally made his stand at Neunkirchen, General Werneck, the Austrian commander, retreated south to the Lahn, and then moved on along the route to Aschaffenbourg, in an attempt to prevent the French from blocking his escape up the Main. General Elsnitz was left at Giessen to act as a rearguard, but when overwhelming French forces threatened him he retreated south in some confusion.
Werneck turned back and posted part of his infantry on the heights of Grüningen, five miles south of Giessen. The first French troops to reach Grüningen were some cavalry and light artillery and skirmishers under General Ney. Ney engaged in a skirmish with the Austrians while he was waiting for the French infantry to catch up, but his artillery got ahead of the skirmishers, and was captured by some Austrian Ulans. This infuriated Ney, who led one his squadrons in an attempt to retake the guns. During the fighting his horse was shot from under him, and he was taken prisoner by the Austrians.
It would be a short lived captivity. On the following day General Hoche discovered that Napoleon had signed the Preliminary Peace of Leoben, and the fighting on the Rhine came to an end. Ney was exchanged on 27 May, after only two months in captivity.