A reader recently wrote to us asking what is the correct title for the heir to the Luxembourgish throne. They saw a tweet by the Prime Minister of Luxembourg, who referred to Prince Guillaume as “Crown Prince” when the reader thought his title was “Hereditary Grand Duke.”
So what is the correct title for the future monarch?
Both “Hereditary Grand Duke” and “Crown Prince” are correct forms according to the Grand Ducal Court.
The French, German and Luxembourgish versions of the Grand Ducal Court’s website lists Prince Guillaume as “The Hereditary Grand Duke” and explain that after his father, Grand Duke Henri, was sworn in as monarch in 2000, Prince Guillaume assumed the title of Hereditary Grand Duke. Throughout the French biography, His Royal Highness is referred to either by the Hereditary Grand Duke title or Prince Guillaume (the title he has held from birth).
However, the English version of the website clearly refers to Guillaume as “The Crown Prince” in the heading, but it also states his title is “Hereditary Grand Duke” in the biography and changes back and forth from calling him “Crown Prince” to “Hereditary Grand Duke”.
The Luxembourgish government and the Grand Ducal Court almost exclusively refer to Guillaume as “Crown Prince” in English and when he is overseas.
Thus, both titles are right. Prince Guillaume is the Hereditary Grand Duke of Luxembourg AND/OR the Crown Prince of Luxembourg – depending on what language you speak.