 Complete the following phrase:  Corbineau entered the Imperial Guard on 12 September 1805, where he served in the Chasseurs à Cheval de la Garde Impériale successively as an adjoint à létat-major assistant to the Staff, then adjudant-major, and finally as a chef descadron. He fought at the battles of Austerlitz 2 December 1805, afterwards receiving promotion to major 18 December 1805, and also at Jena 14 October 1806, 