Prince Michael of Greece and Denmark – Prince Philip the Duke of Edinburgh’s first cousin – has died at the age of 85.

The royal was pronounced dead at a hospital in the Greek capital of Athens, it was announced on Sunday. He will be buried in the capital on Thursday.

Prince Michael was a renowned writer and historian under the name Michel De Gres and was the last remaining grandson of George I, with a lineage to the House of Bourbon through his mother’s side of the family.

The royal was well known for his marriage to Marina Karella, for whom he renounced his right to the Greek throne to marry in 1965.

He is survived by his wife and their two daughters, Princess Olga of Savoy-Aosta and Princess Alexandra of Greece.

Prince Michael was the only child of Prince Christopher and the royal’s second wife, Princess Francoise d’Oleans of France.

His father died at just 51 in 1940 after suffering from a short illness before his mother died in 1953, leaving the royal an orphan by the time he was 14.

He studied political science in Paris before repatriating to Greece for military duty, where he served a term in the Hellenic Coast Guard in order to regain Greek citizenship.

He was the only member of the Greek royal family to remain in the country in 1967 when the government fell to a right-wing military coup after his nephew King Constantine failed in his attempts to overthrow the junta.