Claim: The longest reigning Princess of Thurn and Taxis was  Anna Augusta of Hohenlohe-Waldenburg-Schillingsfürst, while the shortest reigning Princess of Thurn and Taxis was Margarethe Klementine of Austria.
Evidence: Anna Augusta of Hohenlohe-Waldenburg-Schillingsfürst 21 November 1703 21 September 1711 Margarethe Klementine of Austria 15 July 1890 22 January 1952
husband's death