PARIS, FRANCE - MARCH 20: Prince Pierre d'Arenberg, Sibilla Sandra Weiller, Sylvie d'Arenberg Berggruen and Prince Guillaume of Luxembourg attend the mass given in memory of the 100 year anniversary of Prince Ernest Charles D'Arenberg's death in the First World War at Les Invalides on March 20, 2015 in Paris, France. (Photo by Bertrand Rindoff Petroff/Getty Images)
