Depsaix was born in 1768, and began his military career as Chevalier de Veygoux, an officer in the royal army. When Louis XIV fell from power in the early years of the French Revolution Desaix ended up in prison, but during 1793-4 he was released and experienced one of the great rises through the military allowed by the revolution. While with the Army of the Rhine the deputies ignored advice from Paris and promoted Desaix to General, and he established a strong reputation in Germany before he was wounded in 1797 on the Rhine.
When healthy he went to Italy and became trusted by Napoleon, and commanded a division when Napoleon led an army to Egypt. Here Desaix proved an able General once more, considerably aiding Napoleon. When Napoleon returned to France to seize power Desaix remained in Egypt, and was only ordered to return later. Desaix managed to get back to Napoleon in June 1800, when he was given two divisions and sent in the direction of Genoa. However, he was prevented by the weather from going far, and was close enough to the Battle of Marengo to arrive late in the day and order the counter attack which ultimately won and saved Napoleon’s career. Unfortunately Desaix was killed early on. As he was now no threat, Napoleon gave Desaix more of the plaudits than usual.