Finding Prince Charming: When Commoners Marry Royalty

Crown Prince Frederik of Denmark and Mary Elizabeth Donaldson drive off after their engagement at Copenhagen's Amalienborg Palace on October 8, 2013.

Prince William, Duke of Cambridge, embraces wife Kate Middleton during London's Olympic Games on August 2, 2012.

Charlene Wittstock, former Olympic swimmer and current wife of Prince Albert II of Monaco, smiles in a swimming pool on Feb. 10, 1997.

Tatiana Blatnik, Princess of Greece and Denmark, poses at the Giorgio Armani fashion show in Milan on Feb. 25, 2014.

Marie-Chantal, Crown Princess of Greece, arrives at the christening of her son, Odysseas Kimon, in Athens on June 18, 2005.

Maxima Zorreguieta cycles ahead of her then fiance, Crown Prince Willem Alexander of the Netherlands, during a tour of Holland on Sept. 26, 2001.

Mabel Wisse Smit smiles at late husband Prince Friso of Orange-Nassau after their wedding ceremony in Delft, Netherlands on April 24, 2004.

Princess Letizia of Spain waves to photographers at a seminar on Spanish language in journalism in San Millan de la Cogolla, Spain on May 28, 2014.

Silvia Sommerlath, stands with husband King Carl Gustaf of Sweden after their marriage on June 19, 1976.