20th Division ( German Empire ) The 20th Division ( " 20 . Division " ) was a unit of the Prussia n / German Army . It was formed on October 11 , 1866 and was headquartered in Hannover . The division was subordinated in peacetime to the X Army Corps ( " X . Armeekorps " ) . The division was disbanded in 1919 during the demobilization of the German Army after World War I . Recruitment . During the Franco - Prussian War , the division was a mixed unit , with Hannoverian , Brunswick and Westphalian elements . It was subsequently reorganized so that it was recruited primarily from the former Kingdom of Hannover , which had become the Prussian Province of Hanover after 1866 , along with the Duchy of Brunswick . Combat chronicle . During the Franco - Prussian War , the 20th Infantry Division fought in the battles of Mars - la - Tour and Gravelotte , and then in the Siege of Metz . It then fought in the Loire Campaign , including the battles of Beaune - la - Rolande , Orléans , Beaugency - Cravant , and Le Mans . In World War I in 1914 , the 20th Infantry Division fought in the Allied Great Retreat , including the Battle of St . Quentin and the First Battle of the Marne . It was sent to the Eastern Front in 1915 and again twice more , seeing action in the Gorlice - Tarnów Offensive and the Russian Brusilov Offensive . It returned to the Western Front and after a period in the trenches saw action in the Battle of Passchendaele and the German 1918 Spring Offensive . The division was rated a first class division by Allied intelligence . Order of battle in the Franco - Prussian War . During wartime , the 20th Division , like other regular German divisions , was redesignated an infantry division . The organization of the 20th Infantry Division in 1870 at the beginning of the Franco - Prussian War was as follows : Pre - World War I organization . German divisions underwent various organizational changes after the Franco - Prussian War . As noted above , the 20th Division was reorganized to become primarily a Hannover / Brunswick unit . The organization of the 20th Division in 1914 , shortly before the outbreak of World War I , was as follows : Order of battle on mobilization . On mobilization in August 1914 at the beginning of World War I , most divisional cavalry , including brigade headquarters , was withdrawn to form cavalry divisions or split up among divisions as reconnaissance units . Divisions received engineer companies and other support units from their higher headquarters . The 20th Division was again renamed the 20th Infantry Division and its initial wartime organization was as follows : Late World War I organization . Divisions underwent many changes during the war , with regiments moving from division to division , and some being destroyed and rebuilt . During the war , most divisions became triangular - one infantry brigade with three infantry regiments rather than two infantry brigades of two regiments ( a " square division " ) . An artillery commander replaced the artillery brigade headquarters , the cavalry was further reduced , the engineer contingent was increased , and a divisional signals command was created . The 20th Infantry Division ' s order of battle on March 20 , 1918 was as follows :