After feeling unwell, Britain’s 99-year-old Prince Philip was admitted to a London hospital, Buckingham Palace said on Wednesday.

The palace said Queen Elizabeth II’s husband was admitted on Tuesday evening to the private King Edward VII Hospital.

On the advice of Philip’s doctor, it called the admission “a precautionary measure” taken. The palace said that for a few days of “observation and rest,” Philip is expected to remain in the hospital.

Philip, also known as the Duke of Edinburgh, retired in 2017 from government duties and appears rarely in public.

He was staying at Windsor Castle, west of London, with the queen during England’s current coronavirus lockdown.

In 1947, Philip married then-Princess Elizabeth and is British history’s longest-serving royal consort. He has four children, eight grandchildren and nine great-grandchildren, together with the queen.

Philip, a former naval officer and keen polo player, enjoyed robust health well into old age, but in recent years he has had a number of health issues.

In 2011, after suffering chest pains, he was rushed by helicopter to a hospital and treated for a blocked coronary artery. He spent two nights at King Edward VII Hospital in 2017 and was hospitalised for a hip replacement for 10 days in 2018.

In December 2019, Philip was last hospitalised, spending four nights at the King Edward VII Hospital for what the palace said was scheduled treatment of a pre-existing condition.

At the age of 97, after smashing into a car while driving a Land Rover near the Sandringham estate in January 2019, he was forced to give up driving. To get out of the Land Rover, Philip needed assistance, but wasn’t injured. A woman suffered a broken wrist in the other vehicle.