| Unit Name: | 1. Armee 1st Army |
| Dates: | 2 August 1914 – 17 September 1915 19 July 1916 – 24 January 1919 |
| Type: | Army |
| Battles: | World War I
Siege of Antwerp (part) |
| Identification Symbol: | A.O.K. 1 |
| Identification Symbol Label: | Abbreviation |
The 1st Army (German: '''1. Armee / Armeeoberkommando 1 / A.O.K. 1''') was an army level command of the German Army in World War I. It was formed on mobilization in August 1914 from the VIII Army Inspectorate. The army was dissolved on 17 September 1915, but reformed on 19 July 1916 during the Battle of the Somme. It was finally disbanded in 1919 during demobilization after the war.
The 1st Army during World War I, fought on the Western Front and took part in the Schlieffen Plan offensive against France and Belgium in August 1914. Commanded by General Alexander von Kluck, the 1st Army's job was to command the extreme right of the German forces in attacking the left flank of the French Army and encircling Paris, bringing a rapid conclusion to the war. His army had the greatest striking power of the offensive, a density of about 18,000 men per mile of front (about 10 per metre). The First Army captured Brussels on 20 August and was almost successful in defeating France but was halted just 13 miles outside the French capital in the First Battle of the Marne that took place in early September. Von Kluck was replaced in 1915 after being seriously wounded in the leg.
With 10 army level commands (1st to 7th Armies plus three Armee-Abteilungen), the German Supreme Command felt able to dispense with 1st Army. Its units were distributed amongst neighbouring armies and the army was dissolved on 17 September 1915.
2nd Army bore the brunt of the Allied attack in the Battle of the Somme. It had grown to such an extent that a decision was made to divide it. The 1st Army was reformed on 19 July 1916 from the right (northern) wing of the 2nd Army. The former commander of 2nd Army, General der Infanterie Fritz von Below, took command of 1st Army and 2nd Army got a new commander General der Artillerie Max von Gallwitz. Von Gallwitz was also installed as commander of Heeresgruppe Gallwitz – Somme to co-ordinate the actions of both armies on the Somme.
At the end of the war it was serving as part of Heeresgruppe Deutscher Kronprinz.
By the end of the war, the 1st Army was organised as:
| Organization of 1st Army on 30 October 1918 | ||||
|---|---|---|---|---|
| Army | Corps | Division | ||
| ROWSPAN=9 | 1st Army | ROWSPAN=5 | VII Reserve Corps | 1st Division |
| 50th Reserve Division | ||||
| 8th Bavarian Reserve Division | ||||
| 17th Division | ||||
| parts of Guards Cavalry Schützen Division | ||||
| ROWSPAN=2 | VI Reserve Corps | 80th Reserve Division | ||
| Guards Cavalry Schützen Division (less elements) | ||||
| ROWSPAN=2 | XXIV Reserve Corps | 51st Reserve Division | ||
| 7th Division | ||||
The original 1st Army had the following commanders until it was dissolved 17 September 1915:
| 2 August 1914 | VIII Army Inspectorate (VIII. Armee-Inspektion) | Wounded, 27 March 1915 | ||
| 28 March 1915 | 12th Army |
| 19 July 1916 | 9th Army | |||
| 9 June 1918 | 17th Army | |||
| 12 October 1918 | Homeland Defence West | |||
| 8 November 1918 |