1914.
The 20th Division and the 19th Division formed the 10th Army Corps (Hanover).
France.
1. At the outbreak of the war the 20th Division went to the Elsenborn Camp, August 8–10, and entered Belgium on the 11th. It was a part, with the 10th Corps, of the 2d Army (Von Buelow). It fought at Charleroi, at Guise, at St. Quentin. It took part in the battle of the Marne from September 6 to 9 (Congy, Mondement), after which it retired by way of Neufchâtel sur Aisne to the northwest of Rheims. It took up its position between the Aisne and Brimont.
1915.
At the beginning of 1915 it was still holding the lines in the vicinity of Rheims. At the end of March the 164th Infantry Regiment was transferred to the 111th Division (new formation).
Galicia.
2. At the end of April, with its regiments raised to four battalions each, the 20th Division (as well as the 19th Division) was sent to Galacia, where it took part in the operation of Mackensen’s army. It lost very heavily there. From July 28 to September 23 the 11th Company of the 77th Infantry Regiment received at least 133 men as replacements.
France.
3. Brought back to France in September, the 20th Division took part, in the month of October, in the battles in the Champagne.