Born in Königsberg, he joined the army at an early age, but when he was an officer, he was tried for insubordination in court martial, and he was cashiered. He then went on to serve in the Dutch army and participated in a campaign in Malaysia, before re-entering the Prussian army in 1787. In 1806, he took part in a rare Prussian victory in a rear-guard battle at Altenzaun (26 October). He was a lieutenant of Blücher's, and he was made prisoner in Lübeck (7 November). He then became one of the main figures of the regeneration of Prussia. In 1812, he succeeded General Grawert as head of the Prussian “corps” (part of the 10th corps, Marshal Macdonald), which constituted the left wing of the Grande Armée. In December, he began negotiations with the Russians and together they signed the Tauroggen Convention, pretending to believe that Friedrich-Wilhelm III was in agreement. This defection was important both militarily and politically: militarily, because it put Macdonald in a difficult position; and politically, because it was the impulse for Prussia to declare war on France. In 1813-1814, Yorck commanded the first Prussian corps, with which he won the battles of Lakatzbach (26 August, 1813), Möckern, (15 October), Wartenburg (30 October) and Laon (9-10 March, 1814). He was made Count in 1814 and was promoted to the rank of Field Marshal in 1821.
Jacques Garnier, in Tulard Jean, (ed.), Dictionnaire Napoléon, Paris: Fayard, 1987, 2nd edition 1999, p. 977.