Prussian Generalfeldmarschall (field marshal) who led his army against Napoleon I at the Battle of the Nations at Leipzig in 1813 and at the Battle of Waterloo in 1815 with the Duke of Wellington. ALS in German, signed “Blucher,” one page, lightly-lined both sides, 7.25 x 9, April 21, 1806. Untranslated letter to Mr. Schwenke, estate manager at Haltauf, asking him to prepare everything for hunting in September. In very good condition, with intersecting folds, scattered light toning, mild show-through from writing on reverse, and some ink blots and small tears to integral second page. RR Auction COA.