LONDON (AP) — Buckingham Palace officials say Prince Philip, the husband of Queen Elizabeth II, has died. He was 99.

"It is with deep sorrow that Her Majesty The Queen has announced the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh," the palace said. "His Royal Highness passed away peacefully this morning at Windsor Castle."

Philip spent a month in hospital earlier this year before being released on March 16 to return to Windsor Castle.

Philip, also known as the Duke of Edinburgh, married Elizabeth in 1947 and was the longest-serving consort in British history. He retired from public engagements in 2017 after carrying out more than 20,000 of them.

Philip was a member of the Greek royal family and was born on the Greek island of Corfu in 1921. He was an avid sportsman who loved country pursuits. He had four children, eight grandchildren and nine great-grandchildren.

Britain mourned his death on Friday from the moment the BBC interrupted scheduled programming to broadcast the national anthem, “God Save the Queen.”

Soon after the announcement, people began to line up outside Buckingham Palace to see the official death notice that had been attached to the gate. The flag at the palace, the queen’s residence in London, was lowered to half-staff.

British Prime Minister Boris Johnson said Philip “earned the affection of generations here in Britain, across the Commonwealth and around the world.''

“Like the expert carriage driver that he was, he helped to steer the royal family and the monarchy so that it remains an institution indisputably vital to the balance and happiness of our national life,'' Johnson said.

Keir Starmer, leader of the opposition Labour Party, was among the first to offer his condolences, noting Philip’s long record of public service, first as as a naval officer during World War II then during more than 70 years of marriage to the queen.

“He will be remembered most of all for his extraordinary commitment and devotion to The Queen,” Starmer said in a statement.

“For more than seven decades, he has been at her side. Their marriage has been a symbol of strength, stability and hope, even as the world around them changed — most recently during the pandemic. It was a partnership that inspired millions in Britain and beyond.”

World leaders also expressed their sadness. Former U.S. President George Bush and his wife, Laura, offered condolences to the monarch and the entire royal family.

“He represented the United Kingdom with dignity and brought boundless strength and support to the sovereign,'' Bush said in a statement. “Laura and I are fortunate to have enjoyed the charm and wit of his company, and we know how much he will be missed.''