On this day in 1964, King Constantine II married 18-year-old Princess of Denmark Anne-Marie in what continues to be remembered as one of the most extravagant royal weddings in Greece.

The couple tied the knot at the Metropolitan Cathedral in the center of Athens with scores of official guests, royal family members and crowds of onlookers applauding.

Constantine and Anne-Marie’s wedding remains the only one to be held in Greece while including a sitting Greek monarch. The 24-year-old groom had recently taken the thrown after his father King Paul I died on March 6, 1964.

Born in Athens, the newly acceded king was the only son of King Paul and Princess Friederike of Hanover. His wife was the youngest daughter of King Frederick IX of Denmark and Princess Ingrid of Sweden.

Constantine’s accession had been viewed favorably but was cut short by the coup of April 21, 1967 in which the Greek military junta took power.

The coup left Constantine with few options since he did not have military forces at his disposal; therefore, he reluctantly agreed to inaugurate the junta on the condition that it be made up largely of civilian ministers.

But on December 13 1967, Constantine was forced to flee Greece after an unsuccessful countercoup attempt. He remained the formal head of state in exile until the junta abolished the monarchy on June 1, 1973.

Watch the wedding footage