(FILE PHOTO) Diana, Princess of Wales' engagement ring, wedding ring, watch and gold earrings (Photo by Tim Graham Photo Library via Getty Images)
LONDON, ENGLAND - AUGUST 09: Catherine, Duchess of Cambridge watches the Women's Teams Synchronised Swimming Technical Routine on Day 13 of the London 2012 Olympic Games at the Aquatics Centre on August 9, 2012 in London, England. (Photo by Adam Pretty/Getty Images)
COPENHAGEN, DENMARK - OCTOBER 8: Mary Elizabeth Donaldson (L) and His Royal Highness Crown Prince Frederik of Denmark show their engagement ring to the media during a press conference at Fredensborg Castle October 8, 2003 in Copenhagen, Denmark. The pair announced their engagement, with the wedding set for May 14, 2004. (Photo by Scott Barbour/Getty Images)
BORGHOLM, SWEDEN - JULY 14: Crown Princess Victoria of Sweden celebrates her 34th birthday at Solliden on July 14, 2011 in Borgholm, Sweden. (Photo by Christopher Hunt/Getty Images)
COPENHAGEN, DENMARK - OCTOBER 3: Marie Cavallier shows her engagement ring during a press conference attended with Prince Joachim of Denmark to announce their engagement, at the Riddersalen (Great Hall) of the Amalienborg Palace on October 3, 2007 in Copenhagen, Denmark. (Photo by Niels Henrik Dam/Getty Images)
