As a result, the holiday became known as Koningsdag from 2014 on, and the celebration was shifted three days back to 27 April, the King's birthday.
Koningsdag is known for its nationwide vrijmarkt ("free market"), at which the Dutch sell their used items.
In early 1966 Juliana's eldest daughter, Princess Beatrix, married Klaus-Georg von Amsberg.
The marriage was controversial because the new Prince Claus (as he was dubbed) was a German, and Claus himself had served in the German Army during the war.
The incident provoked questions about whether the royal family should continue to participate in the celebrations.