Wikipedia
Prinz-Heinrich-Fahrt
The Prinz-Heinrich-Fahrt (Prince Heinrich Tour, also known as Prince Henry Tour), named after Prince Albert Wilhelm Heinrich of Prussia, was an automobile contest held from 1908 to 1911 and a precursor to the German Grand Prix. The brother of Emperor Wilhelm II, who had staged a Kaiserpreis for automobiles in 1907 (and for other sports also), was an automobile enthusiast and inventor.
Only production touring cars with four seats and three passengers were admitted, no special made race cars. The trophy for the winner was a model car made of 13,5 kg silver.
Ferdinand Porsche himself won in 1910.
The last event was in 1911, not as contest, but as a touristic event.