Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Poniatowski was a nephew of the last king of Poland Stanisław August Poniatowski. He fought with the Grande Armée
Following the defeat of Prussia in 1806-07 he was appointed Minister of War and commander-in-chief of the newly-formed Grand Duchy of Warsaw. Under Napoleon's general leadership he took part in the War of the Fifth Coalition in 1809 and the Invasion of Russia His death at Leipzig gave birth to the Napoleonic legend in Poland, which didn't regain its independence until the end of the First World War. The painting was exhibited at the Salon of 1817.
References
Królewski p.256
Harkett & Hornstein p.209
Jędrysiak p.424
Wandycz p.60
Ruutz-Rees p.46
Bibliography
Harkett, Daniel & Hornstein, Katie (ed.) Horace Vernet and the Thresholds of Nineteenth-Century Visual Culture. Dartmouth College Press, 2017.
Królewski, Zamek. Semper Polonia: l'art en Pologne des lumières au romantisme (1764-1849).. Somogy, 2004.
Jędrysiak, Jacek. Prussian Strategic Thought 1815–1830: Beyond Clausewitz. BRILL, 12 Oct 2020
Ruutz-Rees, Janet Emily. Horace Vernet. Scribner and Welford, 1880.
Wandycz, Piotr S. The Lands of Partitioned Poland, 1795-1918. University of Washington Press, 1975.