Holland's King Willem-Alexander celebrated his 48th birthday in Dordrecht yesterday (27.04.15).

King Willem-Alexander, Queen Maxima and their children

King Willem-Alexander, Queen Maxima and their children

The monarch was joined on the royal barge by wife Queen Maxima, their children Catharina-Amalia, Princess of Orange, 11, Princess Alexia, nine, and Princess Ariane, eight, his brother Prince Constantijn and sister-in-law Princess Laurentien as they kicked off the King's Day festivities in the city.

The king's birthday is a public holiday known as Koningsdag and thousands of well-wishers turned out for the traditional pageant, which always takes place in either Amsterdam or one of the other major cities of the country.

The celebrations, which kick off the night before with special King's Parties, also include flea markets in most towns and people mark the occasion by tucking into an orange pastry called the tompouce.

Koningsdag began in 1890 on 31 August, the birthday of then-monarch Queen Wilhelmina.

When she was succeeded by her daughter Juliana, the date was moved to her birthday, 30 April - and her daughter Beatrix kept the date for her celebration, despite her real birthday being on January 31.

The date was shifted a few days earlier when Willem-Alexander took the throne two years ago following his mother's abdication.