LUXEMBOURG - OCTOBER 20:  Prince Frederik of Denmark and Princess Mary of Denmark attend the wedding ceremony of Prince Guillaume Of Luxembourg and Stephanie de Lannoy at the Cathedral of our Lady of Luxembourg on October 20, 2012 in Luxembourg, Luxembourg. The 30-year-old hereditary Grand Duke of Luxembourg is the last hereditary Prince in Europe to get married, marrying his 28-year-old Belgian Countess bride in a lavish 2-day ceremony.  (Photo by Wolfgang Veerman/David Schwab/Getty Images)