Prince Philip leaves hospital after 4 days of unknown treatment

Dec. 24 (UPI) -- Britain's Prince Philip left King Edward VII's Hospital in London early Tuesday after four nights and has joined Queen Elizabeth II at the royal estate in Sandringham for Christmas.

The 98-year-old Duke of Edinburgh was spotted leaving the central London hospital after days of treatment for what Buckingham Palace said was a "pre-existing condition."

"His Royal Highness would like to thank everyone who sent their good wishes," Buckingham Palace said in a statement.

Prince Philip was admitted Friday for the condition, but Buckingham Palace never specified it or detailed what procedure, if any, he underwent at the hospital. He formally retired from public duties two years ago.

The duke's son, Prince Charles, said Monday he'd been doing "alright" during the hospital stay.

Prince Philip has faced a number of health challenges in recent years. He was involved in a car accident in January, but did not require hospitalization.

King Edward VII's Hospital, a private facility, has been treating Britain's royal family for decades.