COPENHAGEN, Denmark (AP) — Denmark's royal household says the German husband of Queen Margrethe's younger sister, Prince Richard of Sayn-Wittgenstein-Berleburg, has died suddenly. He was 82.

The royal palace said Tuesday that he passed away on Monday at the Berleburg Castle in central Germany where he and his wife, Princess Benedikte, lived.

The cause of death was not given.

Benedikte is the second daughter of late King Frederik and Queen Ingrid, and often represents Margrethe at official events. Benedikte, 72, is eleventh in the line of succession to the Danish throne — one of the world's oldest monarchies.

The couple wed in 1968 in Denmark, and had three children — Prince Gustav, Princess Alexandra, and Princess Nathalie.

No funeral plans were announced.