Duke of Lauenburg

The coat-of-arms as used in 1605, quartered, with quarter 1 and 4 showing the Ascanian barry of ten, in or and sable (starting with the wrong colour in this copy), covered by a crancelin of rhombs (they are not shown in this undetailed copy) bendwise in vert (The crancelin symbolises the Saxon ducal crown.), quarter 2 in azure, showing an eagle crowned in or (Pfalzgraviate of Saxony), and quarter 3 in argent, showing three water-lily leaves in gules, representing the County of Brehna.

The title Duke of Lauenburg derives from the Duchy of Saxe-Lauenburg, which, since its foundation in 1269, has been ruled by twenty-nine dukes of six dynastic houses and lines and by an additional four dukes of a temporary dynastic branch line (Anna Maria Franziska of Saxe-Lauenburg, the first would-be duchess regnant, was kept from inheriting the duchy by male rulers of neighbouring states). For a list of the dukes, illustrated with portraits starting with Julius Henry, see the list of Saxon rulers. For the duchesses consort, see the list of Saxon consorts, also illustrated with some portraits.

The duchy has been held by various countries, including France from 1803 to 1805 and from 1810 to 1814, Prussia from 1805 to 1806, and Westphalia from 1806 to 1810. The kings of Denmark, members of the House of Oldenburg, held the Duchy of Lauenburg from 1814 to 1864, when the territory came under Prussian control in 1864 as a result of the Second Schleswig War, though it was not immediately annexed to Prussia. In 1865, the estates of Saxe-Lauenburg offered rule of the duchy to King William I of Prussia, who accepted the same year, ruling it in personal union until the estates upon decided the merger of their state with Prussia as of July 1, 1876. After the death of the last ruling duke, William I (who after 1870 was also German emperor), in 1888, the now purely honorific title was granted to Otto von Bismarck after his dismissal as Chancellor of Germany in 1890.