Question: Arthur Gerald Wellesley, Earl of Mornington, is the great-great-grandson of what  last German Emperor ("Kaiser") and King of Prussia?
Sentence (from "Prince Wilhelm-Karl of Prussia"): Prince Wilhelm Karl of Prussia ("Wilhelm Karl Adalbert Erich Detloff"; 30 January 1922, in Potsdam – 9 April 2007, in Holzminden) was the third son of Prince Oskar of Prussia, and the last surviving grandson of Wilhelm II, the last German Emperor.
Relevant evidence: No