Princess Margriet, Pieter van Vollenhoven, Prince Floris, Princess Aimee, Prince Pieter-Christiaan and Princess Anita attended the copper anniversary event of Soldier of Orange (Soldaat van Oranje) in Valkenburg. Soldier of Orange is based on the true story of one of the Dutch resistance war fighters, Erik Hazelhoff Roelfzema. The Dutch musical 'Soldier of Orange' premiered on October 30, 2010 with the former Queen Beatrix in attendance.