Question: When is Archduke Joseph August Of Austria's mother's birthday?
Sentence (from "Archduke Joseph August of Austria"): Archduke Joseph August Viktor Klemens Maria of Austria, Prince of Hungary and Bohemia (9 August 1872 – 6 July 1962) was a "Feldmarschall" (Field Marshal) of the Austro-Hungarian Army and for a short period head of state of Hungary.
Relevant evidence: No