Robert was the youngest of ten children of Hermann and Agnes Kosch. After attending the Cadet corps, on 23 April 1874 Kosch graduated as a Sekonde-Leutnant in the Infantry Regiment No. 51 of the Prussian Army. From 1877 to 1880 he studied at the Military Academy. On 3 April 1880 he married Gertrude Noeggerath, with whom he had three daughters.
Career
From 1 April 1881 to 31 March 1887 he was posted as battalion and regimental adjutant to Infantry Regiment No. 132 in Glatz. On 1 April 1887 he was seconded to the General Staff to Berlin. After a number of regimental and staff assignments Kosch was promoted to Oberst in 1905 and later took command of the Infantry Regiment No. 64. In 1909 he was promoted to Generalmajor and assigned to the 78th Infantry Brigade. On 22 April 1912 he was made Generalleutnant and he was appointed commander of the 10th Division in Poznan. After the outbreak of World War I he led his division into the Loraine regionon the Western Front. On 9 October 1914, he became commander of the I. Army Corps in Lithuania, where his troops opposed numerically superior Russian forces. After initial tactical setbacks Kosch and his men finally won the Second Battle of the Masurian Lakes. For this victory Kosch was awarded the Pour le Mérite. On 11 June 1915 he was appointed Commanding General of the X. Reserve Corps. He led them in the battles on the Dniester, the Battle of Gnila Lipa and at Krasnostaw. He transferred to the Balkans Theater, where he fought against Serbia. For his success Kosch received, on 27 November 1915, the Oak Leaves to his Pour le Mérite. At the end of February 1916 the Battle of Verdun began, and Kosch was in it. He was promoted to General der Infanterie on 18 August 1916. Ten days later he assumed command of the newly formed General Command No. 52, a.k.a. the Danube Army; that was used in the Bulgarian Danube region. The multi-day battle at Argesch, in late November to early December 1916, culminating in a Romanian defeat, led to the occupation of Bucharest and the crumbling of Romania's western and northwestern front sectors. From 1 May 1917 on he temporarily led the 9th Army until the arrival of Johannes von Eben. After dissolution of the Danube Army in March 1918 Kosch participated in the occupation of the Ukraine and the struggles against the Red Army. On 1 May 1918 he was appointed commander of all troops in Taurida and the Crimea. Directly after the war he commanded the Border Guard East, effectively all German forces east of Berlin, before he retired from the Army on 10 January 1919. Kosch died in 1942 and was buried in the Invalids' Cemetery. His grave did not survive.
