Buckingham Palace announced the Duke of Edinburgh’s death on Friday, which came after he was hospitalized for a month beginning in February.

“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,” Buckingham Palace said. “His Royal Highness passed away peacefully this morning at Windsor Castle.”

Further information about the prince’s death was not disclosed. In February, Buckingham Palace said the Duke of Edinburgh had been hospitalized as a “precautionary measure” after “feeling unwell.” He was treated for an infection and underwent a “procedure for a pre-existing heart condition,” officials said, and he was released on March 16.

Philip married Elizabeth in 1947 and was “Britain’s longest serving consort,” according to The Associated Press. In 2017, he retired from his public role with the royal family, per NBC News.

Prince Philip, husband of Queen Elizabeth II, has died at 99.

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