XXXIX Reserve Corps (German Empire)

XXXIX Reserve Corps XXXIX. Reserve-Korps
Flag of the Staff of a Generalkommando (1871–1918)
Active	December 1914 - post November 1918
Country	German Empire
Type	Corps
Size	Approximately 26,000 (on formation)
Engagements	World War I

The XXXIX Reserve Corps (German: XXXIX. Reserve-Korps / XXXIX RK) was a corps level command of the German Army in World War I.

XXXIX Reserve Corps was formed in December 1914. It was part of the second wave of new Corps formed in the early stages of World War I consisting of XXXVIII - XXXXI Reserve Corps of 75th - 82nd Reserve Divisions (plus 8th Bavarian Reserve Division). The personnel was predominantly made up of kriegsfreiwillige (wartime volunteers) who did not wait to be called up. It was still in existence at the end of the war.

On formation in December 1914, XXXIX Reserve Corps consisted of two divisions. but was weaker than an Active Corps

In summary, XXXIX Reserve Corps mobilised with 18 infantry battalions, 2 cavalry detachments, 24 field artillery batteries (96 guns), 2 cyclist companies and 2 pioneer companies.

In 1915, the German offensive in Courland was intended to be a diversion while the main effort was made further south by the German 11th Army and Austro-Hungarian 4th Army in the Gorlice–Tarnów Offensive.

Armee-Abteilung Lauenstein (Army Detachment Lauenstein) was formed by upgrading XXXIX Reserve Corps of 10th Army on 22 April 1915. It was named for its commander, Generalleutnant Otto von Lauenstein, who retained simultaneous command of XXXIX Reserve Corps. It was directly under the command of OB East.

Due to its success, it was continuously reinforced until it was raised to the status of an army as the Army of the Niemen on 26 May 1915. Generalleutnant von Lauenstein remained as commander of XXXIX Reserve Corps.

XXXIX Reserve Corps had the following commanders during its existence: