The German Ninth Army in the First World War

The German Ninth Army was an army of Imperial Germany that was formed twice during the war and fought on three fronts. Formed in September 1914 in Silesia, under the command of Paul von Hindenburg and then August von Mackensen, it fought at Warsaw, at Łódź and on the Bzura, and in August 1915 it took Warsaw. Re-formed in 1916 under Erich von Falkenhayn, it defeated the Romanians and entered Bucharest. In 1918 it was moved to the west, where after heavy fighting at Soissons and Noyon it was dissolved in September.

At Warsaw and Łódź (1914)

After Austria-Hungary’s defeat in the Battle of Galicia, Germany decided to support its ally. The greater part of the Eighth Army, victorious in East Prussia, was taken by rail to Upper Silesia. The headquarters of the new Ninth Army was set up on 19 September in Breslau, and Hindenburg took command, with Erich Ludendorff as his chief of staff. It was made up of the XI, XVII and XX Corps and the Guard Reserve Corps, together with reserve, Landwehr and cavalry divisions.

On 28 September the army set off across the Kingdom of Poland towards the middle Vistula, alongside the Austro-Hungarian First Army. In early October it reached the river, and its northern wing, Mackensen’s group, turned on Warsaw and halted a dozen or so kilometres from the city. The Russians had a manifold superiority there, however, so Hindenburg pulled his troops back, and by the end of October the Ninth Army was again close to its starting positions. According to some figures, the Battle of Warsaw and Dęblin cost it about 40,000 men.

On 1 November Hindenburg became commander-in-chief in the East, that is Ober Ost, and Mackensen took over the Ninth Army. Its corps were moved to the area of Thorn, from where on 11 November they struck the flank of the Russian armies.

The army was reinforced at the expense of the Eighth Army, which had to give up two corps, and by cavalry divisions from the west. According to Hindenburg it then numbered about five and a half corps and five cavalry divisions. In the Battle of Łódź the Germans almost encircled the city but failed to close the ring, and their group at Brzeziny itself had to break out of a pocket. The Russians did not leave Łódź until the night of 5–6 December.

On the Rawka and in Warsaw (1915–1916)

In the winter the front froze on the Bzura and the Rawka, west of Warsaw. There, on 31 January 1915, in the Battle of Bolimów, the Ninth Army fired some 18,000 shells filled with tear gas. It was the first time in this war that chemical weapons were used on a large scale, but in the frost the gas barely evaporated and the front did not break.

In April Mackensen left for Galicia to prepare the blow at Gorlice, and the Ninth Army was taken over by Field Marshal Prince Leopold of Bavaria. In the summer, when the great offensive of the Central Powers struck the Kingdom of Poland from the north and from the south, his army pinned the Russians down frontally. When they withdrew, it broke through the ring of Warsaw forts and on 5 August entered the abandoned city. From August its headquarters also directed Prince Leopold’s army group, which pressed on eastwards, and from September it was based at Slonim. On 30 July 1916 the army itself was dissolved.

Romania (1916–1918)

On 27 August 1916 Romania declared war on Austria-Hungary, and its troops entered Transylvania. On 6 September the Ninth Army headquarters was formed anew and sent to Transylvania, and its commander was Falkenhayn, dismissed a few days earlier as Chief of the General Staff. At the end of September the army defeated the Romanians at Hermannstadt, and on 7–9 October it retook Brașov.

The army, made up of German and Austro-Hungarian divisions, including part of the Alpenkorps and Schmettow’s cavalry corps, spent the whole of October trying in vain to cross the passes of the Southern Carpathians. In November General Kühne’s corps broke through the front in the Jiu valley and opened the way for the Ninth Army onto the Oltenian plain. Together with Mackensen’s Danube Army, which had crossed the Danube from Bulgaria, it crushed a Romanian counter-offensive on the Argeș, and on 6 December its troops entered Bucharest. On 8 January 1917 the Germans took Focșani, and the front came to rest on the Putna and the Siret.

In the summer of 1917 the army was commanded by General Johannes von Eben, within Mackensen’s army group. According to Romanian calculations it then numbered 12 divisions, two of them Austro-Hungarian. In August it struck north from the Putna, but in the Battle of Mărășești the Romanians and Russians stopped it and Moldavia was saved. In December the armies of the Romanian front signed the armistice of Focșani, and in the spring of 1918 the Ninth Army stood in north-eastern Romania.

On the Western Front (1918)

On 19 June 1918 the Ninth Army headquarters was moved to the Western Front. The German command put it in between the Oise and the Ourcq, astride the Aisne, where it expected a French counter-stroke towards Soissons. Fritz von Below was appointed the new commander, but he was already gravely ill, so Eben stayed in command, including in the Second Battle of the Marne. On 18 July Mangin’s counter-offensive fell on his troops and on the right wing of the Seventh Army. Eben was ordered to hold Soissons at all costs, but on 2 August the Germans gave up the city and fell back behind the Vesle and the Aisne.

In the second half of August the French attacked the Ninth Army between the Oise and the Aisne in the Second Battle of Noyon and pushed it back behind the Ailette. The army then fell back to the Hindenburg Line. On 18 September 1918 its headquarters was dissolved, and according to Ludendorff its sector was taken over by the neighbouring Seventh Army of the German Crown Prince’s army group.