The Russian–German Legion was a military formation of the Imperial Russian Army raised in 1812 by Peter I, Grand Duke of Oldenburg after being instigated by Alexander I of Russia.
Its first commander was Oberst von Arentsschild, and it was formed from non-French prisoners and deserters left behind in Russia during and after the French invasion earlier that year.
Ernst Moritz Arndt, the private secretary to the pro-Russian Heinrich Friedrich Karl vom und zum Stein, acted as head propagandist to entrants to the Legion.
Ludwig von Wallmoden-Gimborn was now put in command, and the Legion ventured to the lower Elbe, fought at Mecklenburg and Holstein, attacked Harburg and marched far as the Netherlands.
After Napoleon's return from Elba on 26 February 1815, the soldiers of this unit were merged into the 30th and 31st infantry regiment, 8th (Russisch-Deutsche Legion) Ulanenregiment and 18th and 19th horse-artillery batteries of the Prussian army.