Oberste Heeresleitung
After the formation of the German Empire in 1871, the Prussian Army, Royal Saxon Army, Army of Württemberg and the Bavarian Army were autonomous in peacetime, each kingdom maintaining a separate war ministry and general staff to administer their forces. On the outbreak of war, the Constitution of the German Empire made the German Emperor Commander-in-Chief of the combined armies ("Oberster Kriegsherr", Supreme Warlord). The Emperor's role as Commander-in-Chief was largely ceremonial and authority lay with the Chief of the German General Staff, who issued orders in the Emperor's name. The pre-war Chief of the General Staff was Colonel General Helmuth von Moltke (The Younger) and the "Oberste Heeresleitung" was the command staff led by Moltke as Chief of the General Staff of the Army. The General Staff was initially formed into five divisions and two more were created during the war:



In addition to the General Staff of the Field Army, the Supreme Army Command consisted of the Emperor's Military Cabinet, the Intendant General (responsible for supply), senior advisers in various specialist fields (Artillery, Engineers, Medicine, Telegraphy, Munitions and Railways) and representatives from the four German War Ministries and representatives of the other Central Powers. The Emperor was also Commander-in-Chief of the Imperial German Navy, which was led by the German Imperial Admiralty Staff and from August 1918 by the "Seekriegsleitung" (SKL, Naval Warfare Command). Co-ordination was poor at the beginning of the war between OHL and SKL, the navy did not even know about the Schlieffen Plan, an initial attack on France through Belgium. Upon mobilizing in 1914 at the outbreak of World War I, the "Großer Generalstab" (Great General Staff) formed the core of the Supreme Army Command, becoming the General Staff of the Field Army. Colonel General Helmuth von Moltke (The Younger), who had been Chief of the General Staff since 1906, continued in office, as did most of the Division heads. Partially as a result of these longstanding working relationships, Moltke delegated substantial authority to his subordinates, especially to the chiefs of the Operations Division, Colonel Gerhard Tappen, and the Information Division, Lieutenant Colonel Richard Hentsch. These officers were often dispatched to subordinate headquarters to investigate and make decision on behalf of OHL. Although the German armies were victorious in the Battle of the Frontiers their advance was brought to a halt at First Battle of the Marne. Communications between OHL and the front line broke down and Hentsch was dispatched by Moltke to the Headquarters of the First and Second Armies to assess the situation. After discovering the Armies were separated from each other by a gap of twenty-five miles and in danger of being encircled, Hentsch ordered a retreat to the Aisne. On hearing the news from the front, Moltke suffered a nervous breakdown on 9 September. Moltke was replaced by the Prussian Minister of War, Lieutenant General Erich von Falkenhayn, first informally in September and then officially on 25 October 1914. Although Tappen was retained as head of the Operations Division, Falkenhayn brought in two of his own associates, Generals Adolf Wild von Hohenborn and Hugo von Freytag-Loringhoven, into the OHL. Hohenborn served as Generalquartiermeister until January 1915 when he succeeded Falkenhayn as Prussian Minister of War. Freytag-Loringhoven replaced Hohenborn as Generalquartiermeister. Unlike his predecessor, Falkenhayn centralised decision making in his own hands and rarely explained himself to his subordinates; this characteristic has caused historians difficulty in assessing his actual intentions. After taking command Falkenhayn became engaged in the Race to the Sea as the German and Franco-British armies attempted to outflank each other to the north. The campaign culminated at Ypres where both combatants launched major offensives that failed to achieve a breakthrough. Two strategic issues dominated the remainder Falkenhayn's tenure as Chief of the General Staff. First was the priority accorded to the eastern and western fronts. Victories at the Battle of Tannenberg and First Battle of the Masurian Lakes had made Field Marshal Paul von Hindenburg a popular hero and contrasted starkly with the stalemate in the west. Hindenburg and his supporters sought to shift Germany's main effort to the eastern front in hopes of knocking Russia out of the war. Falkenhayn resisted this, believing that France and Great Britain were the true opponents and that a decisive victory against the Russians was impossible. The second concern was the Battle of Verdun, the centrepeice of Falkenhayn's western strategy. Writing after the war, Falkenhayn stated that his intention was to draw the French Army into a battle of attrition and wear them down. However, as the battle developed casualties between the two armies were roughly equal. After the failure of Falkenhayn's strategy at Verdun and the entry into the war of the Kingdom of Romania on the Allied side in August 1916, he was replaced on 29 August by Hindenburg. Paul von Hindenburg's command became known as the "Dritte OHL" (Third OHL) but Hindenburg was "neither the intellectual centre of the strategic planning [...] nor of the new war economy", as proposed in the Hindenburg Programme of 31 August 1916. He was mostly a figurehead and a representative of the military command to the public. Control was mainly exercised by his deputy, General of Infantry Erich Ludendorff, who held the title "Erster Generalquartiermeister" (First Quartermaster General). The duumvirate increasingly dominated decision making on the German war effort, to an extent that they are sometimes described as de facto military dictators, supplanting the Emperor and Chancellor Theobald von Bethmann-Hollweg, whom they managed to have replaced with Georg Michaelis in the summer of 1917. The OHL, through the Hindenburg Programme, a total war strategy, sought decisive victory. Ludendorff ordered the resumption of the unrestricted U-boat Campaign, which, along with the Zimmermann Telegram, provoked the United States to enter the war. The OHL ensured safe passage for Vladimir Lenin and his associates from Switzerland to Russia. After the October Revolution, the OHL negotiated the Treaty of Brest-Litovsk to free troops for the 1918 German spring offensive on the Western Front. As the tide of the war turned against Germany with the Allied Hundred Days Offensive, in late September 1918, Ludendorff called for the "parliamentisation" of the German government and immediate armistice negotiations. When he reversed course and demanded the fight to be resumed in October, Ludendorff was sacked and replaced by Lieutenant-General Wilhelm Groener. Hindenburg remained in office until his resignation from the armed forces in the summer of 1919. As the German Revolution began, Hindenburg and Groener advised the Emperor to abdicate. Groener subsequently came to an agreement with the Social Democrat leader Friedrich Ebert known as the Ebert–Groener pact under which the Army leadership agreed to back the new republican government. With the war over in November 1918, the OHL was moved from Spa to Schloss Wilhelmshöhe in Kassel, to supervise the withdrawal of the German armies from the occupied territories. The final location of the OHL was at Kolberg after February 1919 as the military focus had shifted to preventing territorial encroachment by the Second Polish Republic. In July 1919, the Supreme Army Command and Great General Staff were disbanded by order of the Treaty of Versailles. For a few days, Groener had replaced Hindenburg as Chief of the General Staff, after the latter resigned in late June. He resigned from his position as head of "Kommandostelle Kolberg" (as the staff had become on the formal dissolution of the OHL) in September 1919.
Formation and operation
The Oberste Heeresleitung (, Supreme Army Command or OHL) was the highest echelon of command of the army ("Heer") of the German Empire.