10th Ersatz Division ( German Empire ) The 10th Ersatz Division ( " 10 . Ersatz - Division " ) was a unit of the German Army , in World War I . The division was formed on the mobilization of the German Army in August 1914 . The division was disbanded in 1919 during the demobilization of the German Army after World War I . Formation and recruitment . The 10th Ersatz Division was formed on mobilization from 12 brigade replacement battalions ( " Brigade - Ersatz - Bataillone " ) . Each brigade replacement battalion was numbered after its parent infantry brigade , and was formed with two companies taken from the replacement battalion of each of the brigade ' s two infantry regiments . Thus , collectively , the 12 brigade replacement battalions represented troop contributions from 24 different infantry regiments . The division represented a broad cross - section of the German Empire . The units of the 25th Mixed Ersatz Brigade were from the VII Army Corps area , which included the Prussian Province of Westphalia , the Lower Rhine portion of the Prussian Rhine Province , the Principality of Lippe , and the Principality of Schaumburg - Lippe . The units of the 37th Mixed Ersatz Brigade were from the X Army Corps area , which included most of the Prussian Province of Hanover , the Grand Duchy of Oldenburg , and the Duchy of Brunswick . The units of the 43rd Mixed Ersatz Brigade were from the XI Army Corps area , which included the Hesse - Kassel ( or Hesse - Cassel ) portion of the Prussian Province of Hesse - Nassau , the Grand Duchy of Saxe - Weimar - Eisenach , the Duchies of Saxe - Coburg - Gotha and Saxe - Meiningen , the Principalities of Reuss Elder Line , Reuss Younger Line , Schwarzburg - Rudolstadt , Schwarzburg - Sondershausen , and Waldeck , and portions of the Prussian Province of Saxony , including the region around Erfurt . Combat chronicle . The 10th Ersatz Division initially fought on the Western Front in World War I . It fought in the Battle of the Frontiers , seeing action in Lorraine and against the French defensive line from Nancy to Epinal . From December 1914 to February 1916 , the division occupied the trenchlines in the Woëvre region . The division fought in the Battle of the Somme in September 1916 . After a period in the trenchlines in the Champagne and near Verdun , the division saw action in 1917 in the Second Battle of the Aisne , also called the Third Battle of Champagne , and in the Battle of Passchendaele . In October 1917 , the division was transferred to the Eastern Front , fighting in eastern Galicia until the armistice on that front . In January / February 1918 , the division was in army reserve and was transferred back to the Western Front . It was in the trenchlines in Flanders and the Artois until April 1918 , when it fought in the Battle of Armentières , part of the Battle of the Lys , also known as the German Lys Offensive or the Fourth Battle of Ypres . The division remained in the Flanders / Artois region after the German offensives and faced the various Allied counteroffensives , seeing action in the late - 1918 Battle of Cambrai . It ended the war fighting in the Battle of Valenciennes and in the German retreat to its Antwerp - Meuse position . Allied intelligence rated the division as third class and of moderate value . Order of battle on mobilization . The order of battle of the 10th Ersatz Division on mobilization was as follows : Order of battle on February 20 , 1918 . The division underwent several structural changes as the war progressed . The mixed Ersatz brigades were converted to Ersatz infantry brigades as cavalry , artillery , and pioneer Ersatz units were grouped and reorganized . The brigade replacement battalions were grouped into infantry regiments . The 10th Ersatz Division was triangularized in October 1916 . Cavalry was later reduced , pioneers were increased to a full battalion , and an artillery command and a divisional signals command were created . The division ' s order of battle on February 20 , 1918 was as follows :