The former King of Greece, Constantine II, has been released from hospital after being treated for a bladder infection at the beginning of the week. He was admitted to the Bioclinic in Athens after being taken ill while on the family's annual summer holiday in Porto Cheli in the Peloponnese.
"A follow-up check might be required at a later date," the Greek royal family's website read.
"His Majesty would like to thank Dr Pantazis Kyriazis and the nursing staff at Biokliniki Clinic for their attendance and care."
In May 2009, King Constantine had surgery to unblock an artery and replace one of his heart valves.
He was on the throne from 1964 until the abolition of the Greek monarchy in 1973 following a referendum. That year the King and his wife Queen Anne Marie went into exile in Rome, then Copenhagen before finally settling in London.
The 73-year-old deposed monarch has no objections to Greece being a republic. "If the Greek people decide that they want a republic, they are entitled to have that and should be left in peace to enjoy it," he told Time magazine.
He married Anne Marie in 1964 and the couple went on to have five children including Crown Prince Pavlos and Prince Nikolaos. Originally a Danish princess, she is the sister of the reigning Queen Margrethe.
The King is close friends with his second cousin Prince Charles and is godfather to Prince William. A regular at social royal functions, he attended the Duke of Cambridge's wedding to Kate Middleton in 2011.