Anton Ludwig Friedrich August von Mackensen (born Mackensen; 6 December 1849 – 8 November 1945), ennobled as "von Mackensen" in 1899, was a German field marshal. He commanded successfully 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.
Mackensen was born 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, an administrator of agricultural enterprises, 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, de, was the influential Oberpräsident of East Prussia. They had two daughters and three sons. He found a mentor from 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".