Before her 1986 marriage to Britain's Prince Andrew, Sarah, Duchess of York, was born Sarah Ferguson. She worked in a London public relations firm, an art gallery and then a publishing company before marrying Andrew. The couple divorced in 1996, and while she is no longer a member of the royal family, she still retains her title as a courtesy.
Prince Charles' marriage to Lady Diana Spencer ended in 1996, and for his second marriage, the heir to the throne chose a commoner to be his wife. He married Camilla Parker Bowles, a divorcee with two grown children, on April 9, 2005. She automatically became Princess of Wales upon her marriage, but she prefers to use the lesser title Duchess of Cornwall, to avoid confusion with Diana.
Sophie Helen Rhys-Jones became Sophie, Countess of Wessex, when she married Prince Edward, Earl of Wessex, on June 19, 1999. Edward is the youngest son of Queen Elizabeth II and Prince Philip. She worked in public relations until 2002, when she quit in order to focus on royal duties.
Britain's Princess Anne, the only daughter of Queen Elizabeth II and Prince Philip, married commoners twice. Her first marriage was to Mark Phillips, a British military officer and equestrian. They married on Nov. 14, 1973, and divorced in 1992.
Princess Anne's second marriage was also to a commoner. The Princess Royal married Timothy Laurence, a British naval officer, on Dec. 12, 1992.
Princess Margaret, the younger sister of Britain's Queen Elizabeth II, married photographer Antony Armstrong-Jones on May 6, 1960. The marriage ended in divorce in 1978.
Perhaps the most scandalous instance of a British royal marrying a commoner was Edward VIII of England, who abdicated the throne to marry American-born divorcee Wallis Simpson in 1937. After his abdication, Edward was known as the Duke of Windsor.
Before marrying Prince Rainier of Monaco, Princess Grace was royalty of a different type - an American movie star. The couple wed on April 18, 1956.
Prince Albert II of Monaco will marry South African former Olympic swimmer Charlene Wittstock on July 8, 2011. On her marriage, she will gain the title of Her Serene Highness the Princess of Monaco, a position once occupied by Albert's mother, Grace Kelly.
Princess Grace's daughter, Princess Stephanie of Monaco, also married commoners. Her first marriage was to her bodyguard, Daniel Ducruet - it lasted from 1995-1996.
Princess Stephanie's second marriage was also to a commoner. She married circus performer Adans Lopes Peres, seen at left, on Sept. 12, 2003, and split 10 months later.
Princess Caroline of Monaco's first two marriages were to commoners. First, she wed Parisian baker Philippe Junot in 1978. After their divorce in 1980, she married Stefano Casiraghi (seen here), an Italian sportsman and socialite. He died in a boating accident in 1990. Caroline then married Ernst August, Prince of Hanover in 1999.
Empress Michiko of Japan is the first commoner to marry into the Japanese imperial family. She was born Michiko Shoda, and studied at Harvard and Oxford before marrying Emperor Akihito in 1959.
Japanese Crown Prince Naruhito, right, chose a commonor to be his bride. He married the Harvard-educated Masako Owada, who then became Crown Princess Masako, on June 9, 1993.
Prince Akishino of Japan married Princess Kiko, formerly Kiko Kawashima, on June 29, 1990. Her official title is Her Imperial Highness Princess Akishino.
Prince Felipe of Spain married Princess Letizia on May 22, 2004. Before becoming royalty, Letizia (born Letizia Ortiz Rocasolano) worked as a journalist. She was also married to schoolteacher Alonso Guerrero Perez from 1998-1999.
Before she was Queen of Jordan, Lisa Najeeb Halaby attended Princeton University and worked in architecture and urban planning. She married King Hussein on June 15, 1978. Since her husband's death in 1999, she has been queen dowager of Jordan.
Jordan's current monarch, King Abdullah II, also chose a commoner to be his wife - he married Rania al Yassin in 1993. Before her marriage, Queen Rania earned a degree in business administration from the American University in Cairo and worked for Citibank and Apple.
Princess Victoria of Sweden married her personal trainer, Daniel Westling, on June 19, 2010. News of their relationship was first reported in 2002, and they announced their engagement in February 2009. Daniel's official title is now His Royal Highness Prince Daniel, Duke of Vastergotland.
Before Crown Princess Mette-Marit married Crown Prince Haakon and entered Norway's royal family, she had a party-filled past, including a son by an ex-partner with drug convictions. She met Crown Prince Haakon at the country's largest rock festival. Before her wedding, she tearfully apologized for her wild days.
Before she became Crown Princess of Denmark, Mary Elizabeth Donaldson was an Australian advertising executive turned estate agent. She met Crown Prince Frederik at a bar in Sydney during the 2000 Summer Olympics. They married on May 14, 2004.
Dutch Crown Prince Willem-Alexander married Princess Maxima on Feb. 2, 2002. Born Maxima Zorreguieta in Argentina, she earned a degree in economics in Argentina and worked as an investment banker before her marriage. The Dutch parliament nearly blocked their marriage when news broke that her father had ties to Argentina's military dictatorship in the 1970s.
Prince Nikolaos of Greece and Denmark married 29-year-old event planner Tatiana Blatnik on August 25, 2010. The wedding took place on the Greek island of Spetses. On her marriage, Blatnik became officially styled as Princess Tatiana of Greece and Denmark.
Prince Friso of the Netherlands had to give up his position as second in line to the throne when he married Princess Mabel in 2004. The drastic measure was due to the Dutch government's refusal to approve the marriage after Mabel (born Mabel Wisse Smit) gave false information about a alleged relationship she had with a drug dealer.
Prince Joachim of Denmark married commoners twice. His first marriage was in 1995, to Hong Kong-born sales and marketing executive Alexandra Christina Manley. After they divorced in 2005, he married Paris-born Marie Cavallier, now Princess Marie of Denmark (seen here), in 2008. Before her marriage, she worked in New York as an international marketing coordinator.
Princess Lalla Salma of Morocco worked as an information services engineer before marrying King Mohammed VI on March 21, 2002, and becoming the princess consort. She is the first wife of a Moroccan ruler to be acknowledged publicly and given a royal title.