The Duke of Edinburgh, Prince Philip, has left hospital following his heart scare, Buckingham Palace said.
"He will be rejoining the Queen and other members of the royal family at Sandringham," said a palace spokeswoman.
The duke's recent heart trouble has been his most serious health scare yet, even though the 90-year-old is renowned for being robust and active.
The duke was admitted to Papworth Cardiothoracic Hospital in Cambridge on Friday for precautionary tests after complaining of chest pains.
He was found to have a blocked coronary artery which had caused his pain.
He was treated successfully by coronary stenting and remained in hospital under observation.
He is said to have been disappointed to miss the traditional Christmas Day service and Boxing Day shoot at Sandringham. He plays a major role in both events.
While the duke was said to be "itching" to get home, the hospital said his condition remained good and that keeping him for a fourth night was simply a "precautionary measure".
Members of the royal family visited him in hospital on Christmas Eve. The Queen, the Duke of York, the Earl of Wessex and the Princess Royal arrived from Sandringham by helicopter and stayed for 45 minutes.