Arthur Gerald Wellesley, Earl of Mornington, is the great-great-grandson of what  last German Emperor ("Kaiser") and King of Prussia?
Arthur Wellesley, Earl of Mornington Arthur Gerald Wellesley, Earl of Mornington (born 31 January 1978 at St Mary's Hospital in Paddington, London) is the son of Charles Wellesley, 9th Duke of Wellington. The Wellesleys are an aristocratic Anglo-Irish family. Through his mother, Antonia von Preussen, Duchess of Wellington, he is great-great-grandson of Kaiser Wilhelm II. As a descendant of Queen Victoria, he is eligible to succeed to the British throne.
Frederick II, Grand Duke of Baden Frederick II (9 July 1857 – 9 August 1928) was the last sovereign Grand Duke of Baden, reigning from 1907 until the abolition of the German monarchies in 1918.