INTERNET SOURCE: https://en.wikipedia.org/wiki/August_von_Mackensen
Anton Ludwig August von Mackensen (6 December 1849 – 8 November 1945), born August Mackensen, was a German soldier and field marshal. He commanded with success during the First World War and became one of the German Empire's most prominent military leaders. After the Armistice, Mackensen was interned for a year. He retired from the army in 1920 and was made a Prussian state councillor in 1933 by Hermann Göring. During the Nazi era, Mackensen remained a committed monarchist and sometimes appeared at official functions in his First World War uniform. He was suspected of disloyalty to the Third Reich, although nothing was proven against him.