Prince Philip, Queen Elizabeth II’s husband of 72 years, on Wednesday marked his 99th birthday .
Philip, whose official title is the Duke of Edinburgh, is expected to celebrate in private, with no public events scheduled.
The queen and Philip left London for Windsor Castle in April, as a sensible precaution amid the Covid-19 pandemic, the royal family said.
He is the oldest and the longest-serving consort in British history, described by the 94-year-old queen as her `constant strength and guide’.
His eldest son, Prince Charles, heir to the throne, wished him a happy birthday via Twitter, as did his grandson, Prince William and his wife Kate, the Duchess of Cambridge.
Buckingham Palace issued a new photograph of Philip and the queen together, taken at Windsor Castle in 2019.
Philip, who is popular with the public, is known for his strong sense of duty.
He has attended few engagements with the queen, since announcing his retirement from most public duties in May 2017.
He was not seen during a royal banquet and other events, to mark a state visit to Britain last year by U.S. President Donald Trump and his family.
The queen and Philip have four children, eight grandchildren, and eight great-grandchildren.