Born in Montpellier, France, of a noble family, he joined the French army in 1773 and entered upon active service in 1780, as aide-de-camp to Rochambeau in the American Revolutionary War.

The National Constituent Assembly entrusted him with the command of the escort which conducted King Louis XVI to Paris after the Flight to Varennes (June 1791).

Returning after a brief interval, under the apprehension that his father-in-law would be held responsible for his absence, he arrived in Paris in the midst of the Reign of Terror, and had to flee to Switzerland.

After the coup of the 18th Fructidor (4 September 1797) Dumas, being proscribed as a monarchist, made his escape to Holstein, where he wrote the first part of his Précis des événements militaires (published anonymously at Hamburg, 1800).

[1] Obliged to retire after the restoration of Louis XVIII (1815), Dumas devoted his leisure to the continuation of his Précis des événements militaires, of which nineteen volumes, embracing the history of the war from 1798 to the peace of 1807, appeared between 1817 and 1826.

A growing weakness of sight, ending in blindness, prevented him from carrying the work further, but he translated Napier's Peninsular War as a sort of continuation to it.