LONDON -- Princess Anne, the daughter of Queen Elizabeth II, began divorce proceedings Monday after a two-year separation from her husband, Capt. Mark Phillips, Buckingham Palace said.
The divorce, after 18 years of marriage, marks the third failed marriage in the British royal family. Princess Margaret, the queen's sister, was divorced in 1978. Last month the palace announced the duke and duchess of York -- Prince Andrew and the former Sarah Ferguson -- planned to separate.
The marriage of the queen's son, Prince Charles, to Princess Diana, meanwhile, is widely reported to be under strain. The queen's youngest son, Prince Edward, is single.
'Her Royal Highness the Princess Royal and Capt. Mark Phillips have agreed, after more than two years of separation that their marriage should be formally ended. Accordingly, Her Royal Highness is starting the necessary legal proceedings,' a palace spokeswoman said.
The princess, the second child of the queen and Prince Philip, filed divorce papers Monday, she said.
Princess Anne, 51, married Phillips on Nov. 14, 1973. Their two children, Peter, 14, and Zara, 9, will continue to live with their mother at their home, Gatcombe Park, the spokeswoman said.
Phillips will continue to have unlimited access to visit his children and will continue to live at Aston Farm on the Gatcombe estate, the palace said.
When Buckingham Palace announced the separation in August 1989, it said the couple had 'decided to separate on terms agreed between them. There are no plans for divorce proceedings.'
The palace would not comment on whether the princess planned to remarry, saying her plans were 'a purely personal and private matter.'
Earlier this year, New Zealand art teacher Heather Tonkin, 38, brought a paternity suit against Phillips in New Zealand, claiming he was the father of her 6-year-old daughter. The captain said he would contest the suit.
Shortly before the couple's 1989 separation, private letters written to Princess Anne by a naval commander were leaked to the press, causing a scandal and putting in question the future of the marriage.
The princess, who won the European Three-Day-Event riding championship in 1971, was the only member of the British royal family in modern times to become a world-class athlete.
It was her interest in riding that led to romance with Phillips, a champion rider and son of the director of a sausage-making firm. They were married at Westminster Abbey Nov. 14, 1973.