LONDON — Prince Philip, the Duke of Edinburgh, has left King Edward VII"s Hospital in London one month after he was first admitted. The 99-year-old, who had heart surgery earlier this month, is in "good spirits" after being discharged on Tuesday, a royal source said. He has now returned to Windsor Castle, according to a statement from Buckingham Palace. Philip, who was first admitted to King Edward VII"s Hospital on Feb. 16, had been recovering at the private facility after having heart surgery at St Bartholomew"s Hospital. "His Royal Highness wishes to thank all the medical staff who looked after him at both King Edward VII"s Hospital and St Bartholomew"s Hospital, and everyone who has sent their good wishes," the statement added. A royal source told CNN last month that his hospital admission was not an emergency and was not related to COVID-19. Philip is married to Queen Elizabeth II and both have received at least one dose of a COVID-19 vaccine. Philip, who turns 100 in June, stepped back from public life in 2017 and has been taken to the hospital several times in recent years. In December 2019, he received hospital treatment for a pre-existing condition. The Queen and her husband have spent most of the past year at Windsor Castle, outside London, having moved away from Buckingham Palace during the first wave of the COVID-19 pandemic in spring 2020. In April 2020, the Duke of Edinburgh made a rare public statement, thanking key workers across the UK. Philip was born in Corfu, Greece, in 1921 and has English, Russian, German/Prussian, and Danish ancestry. He and Queen Elizabeth married on Nov. 20, 1947.