Prince Henry of Prussia (1862–1929) became the club's patron. Henry was interested in motor cars as well and supposedly invented a windshield wiper and, according to other sources, the car horn. In his honor, the "Prinz-Heinrich-Fahrt" (Prince Heinrich Tour) was established in 1908, like the earlier Kaiserpreis a precursor to the German Grand Prix. Henry and his brother William gave patronage to the Kaiserlicher Automobilclub (Imperial Automobile Club). Henry also was an early proponent of introducing submarines and airplanes. He had merchant ships converted into seaplane tenders for operations in the Baltic Sea. Henry respected his brother, but this attitude was not returned in the
Prince Joachim of Prussia Schönaich-Carolath (25 November 1918 – 16 March 1972). They divorced on 5 September 1946. They were the parents of three children: After the divorce, Prince Karl married, morganatically, Luise Dora Hartmann (5 September 1909 – 23 April 1961) on 9 November 1946. The childless couple divorced in 1959. Prince Karl's last marriage was to Doña Eva Maria Herrera y Valdeavellano (10 June 1922 – 6 March 1987) on 20 July 1959 in Lima, Peru. They were married until Prince Karl's death and had two daughters; Prince Joachim of Prussia Prince Joachim Franz Humbert of Prussia (17 December 1890 – 18