(FILES) In this file photo taken on May 19, 2011 Prince Philip, the Duke of Edinburgh is pictured during a tour of the Irish National Stud in Kildare, on the third day of the Queen's four-day visit to Ireland. - Prince Philip, the 98-year-old husband of Queen Elizabeth II, went into hospital on Friday, December 20, 2019 for precautionary treatment on a pre-existing condition, Buckingham Palace said. (Photo by Paul ELLIS / AFP)