Prince Philip’s cause of death has been confirmed.
The 99-year-old royal died of “old age,” according to The Telegraph, which reportedly obtained his death certificate.
The death was certified by Sir Huw Thomas, the head of the royal medical household and the physician to the Queen.
Typically, the term “old age” is acceptable as a cause of death if the patient is over 80 years old and if the physician has personally cared for them over a long period, The Telegraph reported.
Sir Huw Thomas has been caring for the Duke of Edinburgh and Queen Elizabeth since 2014.
Philip, who would have turned 100 in June, had been plagued by health issues in recent years after retiring from his public duties in August 2017.
He abruptly canceled his appearance at the traditional Maundy church service that he was scheduled to attend with the monarch in March 2018. Philip also skipped Easter Sunday services that year ahead of the announcement that he underwent hip replacement surgery.
The royal had a car accident in January 2019 that resulted in him voluntarily giving up his license. That December, he was hospitalized in relation to a “pre-existing condition,” the palace said at the time.
He was again admitted to King Edward VII hospital on Feb. 16 to undergo a few days of observation and rest after “feeling unwell” and being “treated for an infection,” according to Buckingham Palace. This resulted in the prince’s longest ever hospital stay: 28 days.
A funeral was held for Philip on April 17.
Philip is survived by Queen Elizabeth, his wife of 73 years, their daughter Princess Anne and their three sons: next-in-line-to-the-throne Prince Charles, Prince Andrew, and Prince Edward.
He also leaves behind eight grandchildren, including Prince William and Prince Harry, and nine great-grandchildren, including Prince George, Princess Charlotte, Prince Louis, Archie, and Princess Eugenie’s new baby boy, August, whose middle name is Philip.