French soldiers line a sunlit ridge as cannon smoke billows around an old windmill under heavy, almost black storm clouds. In the foreground, mounted officers gather near a farmhouse, two dead horses lie on the road, and figures cluster by the house at the left. The Battle of Valmy, on September 20, 1792, was the French army's first major victory in the wars that followed the Revolution: the Prussian advance on Paris, led by the Duke of Brunswick, was halted near the village. Horace Vernet painted it for the duc d'Orléans, the future King Louis-Philippe, who had fought there.

The duc and his younger brother, the duc de Montpensier, appear slightly left of center, reporting on the battle to the comte de Rochambeau. Vernet completed it in April 1826 and received 10,000 francs for it. The National Gallery says the victory helped ensure the Revolution's survival: within two days the monarchy was abolished and the First French Republic proclaimed. This was the last of four battle scenes Vernet painted for the duke.

It was bequeathed to the National Gallery in 1914 by Sir John Murray Scott. It belongs to the National Gallery in London.