 Complete the following phrase:  While on the staff of Sir Robert Wilson he was present with the Russian army at the retreat of the French cavalry from Moscow in October 1812. In 1813 he was at the battles of Lützen, Bautzen, Dresden, Kulm, Wurzen, and the Siege of Hamburg and the operation at Holstein. In 1815 he was appointed quartermaster general to the Prince of Orange, under whom he served in the 1st Kings Dragoon Guards and was present at the battles at 