Anton Ludwig Friedrich August Mackensen (ennobled as von Mackensen in 1899; 6 December 1849 – 8 November 1945), was a German field marshal. He commanded Army Group Mackensen during World War I (1914–1918) and became one of the German Empire's most prominent and competent military leaders. After the armistice of 11 November 1918, the victorious Allies interned Mackensen in Serbia for a year. In 1920, he retired from the army. In 1933 Hermann Göring made him a Prussian state councillor. During the Nazi era (1933–1945), Mackensen remained a committed monarchist and sometimes appeared at official functions in his World War I uniform. Senior Nazi Party members suspected him of disloyalty, but nothing was proven against him.
Anton Ludwig Friedrich August Mackensen was born on 6 December 1849 in Haus Leipnitz, near the village of Dahlenberg (today part of Trossin) in the Prussian Province of Saxony, to Ludwig and Marie Louise Mackensen. His father, a farm secretary, sent him to a Realgymnasium in Halle in 1865, seemingly in the hope that his eldest son would follow him in his profession.
Mackensen began his military service in 1869 as a volunteer with the Prussian 2nd Life Hussars Regiment (Leib-Husaren-Regiment Nr. 2). During the Franco-Prussian War of 1870–1871, he was promoted to second lieutenant and won the Iron Cross Second Class for leading a charge on a reconnaissance patrol north of Orléans. After the war, he left the service and studied at Halle University but returned to the German Army in 1873 with his old regiment.
He married Doris (Dorothea) von Horn, the sister of a slain comrade, in 1879. Her father, Karl von Horn, was the influential Oberpräsident of East Prussia. They had two daughters and three sons. He found a mentor in the War Minister Julius von Verdy du Vernois. In 1891, Mackensen was appointed to the General Staff in Berlin and bypassed the usual three-year preparation in the War Academy. His chief, Helmuth von Moltke, found him a "lovable character".
Mackensen was recalled from the regiment to serve as an adjutant to the next chief, Alfred von Schlieffen (in office 1891–1906), whom he regarded as a great instructor on how to lead armies of millions.
Mackensen impressed Kaiser Wilhelm II, who ordered that he be given command of the 1st Life Hussars Regiment (Leib-Husaren-Regiment Nr. 1) from 17 June 1893, and when he left its command on 27 January 1898 he was retained à la suite, often wearing the distinctive death's head uniform thereafter. Mackensen, then became adjutant to Wilhelm II, the first commoner to hold that position. For the next three-and-a-half years, he shadowed the Kaiser and met the high and mighty of Germany, the rest of Europe and the Near East. His sons were schooled with the Kaiser's. Mackensen was ennobled on the Kaiser's 40th birthday, 27 January 1899, and became August von Mackensen.
Next, he received the command of the newly created Life Hussar Brigade (Leib-Husaren-Brigade) from 1901 to 1903, and from 1903 to 1908, he commanded the 36th Division in Danzig.
His wife died in 1905, and two years later, he married Leonie von der Osten, who was 22 years old. When Schlieffen retired in 1906, Mackensen was considered as a possible successor, but the position went to Helmuth von Moltke the Younger. In 1908, Mackensen was given command of the XVII Army Corps, headquartered in Danzig. The Crown Prince was placed under his command, and the Kaiser asked Mackensen to keep an eye on the young man and to teach him to ride properly.
At the outbreak of war in 1914, Mackensen, aged 65, commanded the XVII Army Corps, which became part of the German Eighth Army in East Prussia, under General Maximilian von Prittwitz, and then, 21 days later, under General Paul von Hindenburg. Mackensen had his corps moving out on a 25 km march to the Rominte River within fifty minutes of receiving his orders on the afternoon of 19 August 1914, after the Imperial Russian Army had invaded East Prussia. He led the XVII Corps in the battles of Gumbinnen (20 August 1914), Tannenberg (23 to 30 August 1914) and the First Battle of the Masurian Lakes (2 to 16 September 1914), which drove the invading Russians out of most of East Prussia.
On 2 November 1914, Mackensen took over command of the Ninth Army from Hindenburg, who became Supreme Commander East (Oberbefehlshaber Ost). On 27 November 1914, Mackensen was awarded the Pour le Mérite, Prussia's highest military order, for successful battles around Warsaw and Łódź.
By April 1915, the Russians had conquered much of western Galicia and were pushing toward Hungary. In response to the desperate pleas from Vienna, German Chief of Staff Erich von Falkenhayn agreed to an offensive against the Russian flank by an Austro-German army under a German commander. The reluctant Austro-Hungarian supreme command agreed that the tactful Mackensen was the best choice for commanding the coalition army. Army Group Mackensen (Heeresgruppe Mackensen) was established, containing a new German Eleventh Army, also under his command, and the Austro-Hungarian Fourth Army. As chief of staff, he was assigned Hans von Seeckt, who described Mackensen as an amiable, "hands-on commander with the instincts of a hunter". His army group, which had an overwhelming advantage in artillery, smashed through the Russian lines between Gorlice and Tarnow and then continued eastward. Never giving the Russians time to establish an effective defence, it retook most of eastern Galicia, recapturing Przemyśl and Lemberg. The joint operation was a great victory for the Central Powers, which advanced 310 km (186 mi), and the Russians pulled out of all of Poland soon afterward.
Mackensen was awarded oak leaves to his Pour le Mérite on 3 June 1915 and was promoted to field marshal on 22 June. He also received the Order of the Black Eagle, Prussia's highest-ranking order of knighthood, as well as numerous honours from other German states – including the Grand Cross of the Military Order of Max Joseph, the highest military honor of the Kingdom of Bavaria, on 4 June 1915 – and from Germany's allies.
In October 1915, a new Army Group Mackensen (Heeresgruppe Mackensen, which included the German Eleventh Army, the Austro-Hungarian Third Army and the Bulgarian First Army), launched a renewed campaign against Serbia. The campaign impacted military resistance in Serbia but failed to remove the Royal Serbian Army, half of which managed to retreat to Entente-held ports in Albania and, after recuperation and rearmament by the French and the Italians, re-entered fighting on the Macedonian front. When Mackensen returned to Vienna, he was honoured by a dinner and a personal audience with Emperor Franz Joseph I of Austria and was decorated with the jeweled Military Merit Cross 1st Class with Diamonds, an uncommon award for a foreigner.
Mackensen appears to have had great respect for the Serbian Army and Serbs generally. Before departing to the Serbian front in 1915, he had spoken to his men:
You are not going to the Italian, Russian, or French front. You are going into battle against a new enemy - dangerous, tough, fearless, and sharp. You are going to the Serbian front and Serbia. Serbs are people who love their freedom, and who will fight to the last man. Be careful this small enemy does not cast a shadow on your glory and compromise your successes.
After Romania declared war on Austria-Hungary on 15 August 1916, Mackensen was given command of a multinational army, with General Emil von Hell as chief of staff, of Bulgarians, Ottomans, Austro-Hungarians and Germans. It assembled in northern Bulgaria and then advanced into Dobruja. By 8 September, it had taken the two major forts on the right bank of the Danube, the first in a single day by a force that was outnumbered by the besieged, who were overwhelmed by Mackensen's artillery. Then, a German and Austro-Hungarian army group that was commanded by Falkenhayn broke into Wallachia through the Vulkan Pass in the Transylvanian Carpathian Mountains while Mackensen crossed the Danube by seizing bridgeheads on the left bank to shield the Austro-Hungarian engineers who built the long pontoon bridge. The Romanian Army and its Russian allies were forced back between those pincers. After three months of war, two thirds of Romania was occupied by the Central Powers. The capital of Romania, Bucharest, was captured by the Central Powers on 6 December 1916, on his 67th birthday. He rode in on a white horse and moved into the Romanian royal palace. For that performance, on 9 January 1917, Mackensen was awarded the Grand Cross of the Iron Cross and became one of only five recipients of that honour in the First World War. Since he now wore every Prussian medal, the Kaiser decided to name a battle cruiser after him, which became the first in a new class. Mackensen became the military governor of the large part of Romania (mainly Wallachia) that was occupied by the Central Powers. He proposed making a German prince the King of Romania, but the initiative fell through. His last campaign was an attempt to destroy the Romanian Army, which had been reorganised.