Prince Charles Edward book (1900) by Andrew Lang. George Keith, 10th Earl Marischal (1692, probably at Inverugie Castle - 1778, Potsdam) was a Scottish and Prussian army officer and diplomat. Jacobite by persuasion, he was tenth and last Earl Marischal, having inherited the title from his father the 9th earl in 1712. He served in Flanders under the duke of Marlborough (1708-1711), but for considering placing the Old Pretender on the British throne on Queen Anne's death, he was deprived of his commission (or resigned). He fought on the Jacobite side during the 1715 Jacobite rising and was attainted for treason by the Hanoverian government, with his estates falling to the crown. He fled to the continent and served the Jacobite court at Avignon and was ambassador to Spain and then Prussia. He served Frederick the Great as his ambassador to Spain from 1759 to 1761 informing the Hanoverian government of Spanish preparations to enter the war on France's side, which gained him his pardon by George II on 29 May 1759.