Page "Grand Ducal Family of Luxembourg" Paragraph 3

The male-line descendants of Grand Duchess Charlotte who are the children of a reigning Grand Duke or The Hereditary Grand Duke hold the titles Prince ( ss ) of Luxembourg and Prince ( ss ) of Nassau with the style of His / Her Royal Highness.

Male line descendants of Grand Duchess Charlotte who are not the children of a Grand Duke or Hereditary Grand Duke are Prince ( ss ) of Nassau with the style of His / Her Royal Highness ( coming from their status as male-line descendants of Duke Robert of Parma ).

The title Prince of Bourbon-Parma was relinquished by Grand Duke Jean in 1986, but he and his relatives kept the style of His / Her Royal Highness.