Prince Philip, the husband of the United Kingdom’s Queen Elizabeth II, has died at the age of 99, Buckingham Palace announced Friday.
Philip, who was due to celebrate his 100th birthday in June, had been by his wife’s side throughout her 69-year reign, the longest in British history.
A statement from the palace said Philip passed away peacefully at Windsor Castle on Friday morning.
The Duke of Edinburgh, as he was officially known, married Elizabeth in 1947, and played a key role in modernizing the monarchy in the post-World War II period.
Philip left hospital last month after receiving treatment at St Bartholomew’s Hospital in London for a pre-existing heart condition.
Philip retired from public duties in 2017 and has rarely appeared in public since.