Greece's former King Constantine II, who ruled before the country became a republic in 1974, died in Athens on Tuesday at the age of 82.
Greek public broadcaster ERT said Constantine, a cousin of British monarch King Charles III, died "of a stroke."
According to Greek media, he was taken to an Athens hospital last week with breathing problems.
Way to the throne
Constantine was born on June 2, 1940, in Athens to Prince Paul, younger brother to King George II and heir presumptive to the throne, and princess Federica of Hanover. Before Constantine's first birthday, the royal family was forced to flee Greece during the German invasion in World War II.
King George II returned to Greece in 1946 following a disputed referendum, but
died a few months later, making Constantine the heir to King Paul I. King Paul I died of cancer on March 6, 1964, and Constantine succeeded him.
Short reign
The youthful monarch, who had already achieved glory as an Olympic gold medalist in sailing, was hugely popular. But much of that support was squandered due to his active involvement in the political machinations.
Following the 1967 military coup, Constantine was forced into exile after he led an unsuccessful countercoup.
A year later, a referendum by the national unity government on abolishing the monarchy dashed any hopes that Constantine had of reigning again.