The XIII Corps of the Ottoman Empire (Turkish: 13 ncü Kolordu or On Üçüncü Kolordu) was one of the corps of the Ottoman Army. It was formed in the early 20th century during Ottoman military reforms. Formation Order of battle, 1911 With further reorganizations of the Ottoman Army, to include the creation of corps level headquarters, by 1911 the XIII Corps was headquartered in Baghdad. The Corps before the First Balkan War in 1911 was structured as such: XIII Corps, Baghdad 37th Infantry Division, Baghdad 109th Infantry Regiment, 110th Infantry Regiment, vicinity of Baghdad 111th Infantry Regiment, Baghdad 37th Rifle Battalion, Najaf 37th Field Artillery Regiment, Baghdad 37th Division Band, Baghdad 38th Infantry Division, Basra 112th Infantry Regiment, Basra 113th Infantry Regiment, Amara, Baghdad 114th Infantry Regiment, Müntafik 38th Rifle Battalion, vicinity of Baghdad Field Artillery Battalion, Baghdad Units of XIII Corps 14th Cavalry Brigade, Baghdad 33rd Cavalry Regiment, Baghdad 34th Cavalry Regiment, Baghdad 35th Cavalry Regiment, Baghdad 25th Mountain Artillery Battalion, Baghdad 13th Engineer Company, Baghdad 13th telegraph Company, Baghdad 13th Transport Battalion, Baghdad Border companies x 6 World War I Order of battle, August 1914 In August 1914, the corps was structured as follows: XIII Corps (Mesopotamia) 37th Division Order of battle, November 1914 In November 1914, the corps was structured as follows: XIII Corps (Moving to Third Army) 37th Division Order of battle, late summer 1915 In the late summer of 1915, the corps was structured as follows: XIII Corps (Mesopotamia) 35th Division, 38th Division Order of battle, January 1916 In January 1916, the corps was structured as follows: XIII Corps (Mesopotamia) 35th Division, 52nd Division Order of battle, August 1916, December 1916 In August 1916, December 1916, the corps was structured as follows: XIII Corps (Mesopotamia) 2nd Division, 4th Division, 6th Division Order of battle, August 1917, January 1918, June 1918, September 1918 In August 1917, January 1918, June 1918, September 1918, the corps was structured as follows: XIII Corps (Mesopotamia) 2nd Division, 6th Division After Mudros Order of battle, November 1918 In November 1918, the corps was structured as follows: XIII Corps (Mesopotamia) 2nd Division, 6th Division Order of battle, January 1919 In January 1919, the corps was structured as follows: XIII Corps (Mesopotamia, Diyâr-ı Bekir) 2nd Division (Salur) 14th Infantry Regiment, 15th Infantry Regiment, 24th Infantry Regiment 5th Division (Mardin) 1st Infantry Regiment, 6th Infantry Regiment, 18th Infantry Regiment 12th Cavalry Regiment Sources Corps