Frederick William Kettler, Duke of Courland (19 July 1692 – 21 January 1711), married to Grand Duchess Anna Ioannovna of Russia. Leopold Charles Kettler (14 December 1693 – 21 July 1697). Notes References Sources Dukes of Courland 1650 births 1698 deaths 17th-century Latvian people People from Jelgava Burials in the Ducal Crypt of the Jelgava Palace