Koningsdag or King's day is a national holiday in the Kingdom of the Netherlands. Celebrated on 27 April, the date marks the birth of King Willem-Alexander. When the Dutch monarch is female, the holiday is known as Koninginnedag ( ) or Queensday and, under Queen Beatrix until 2013, was celebrated on 30 April. She prolonged the tradition that was born under her mother's reign: Queen Juliana's birthday was on 30 April.