Youngest son of Beatrix of the Netherlands and Claus von Amsberg; brother of King Willem-Alexander of the Netherlands
According to Wikipedia,
Prince Constantijn of the Netherlands is the third and youngest son of the former Dutch queen, Beatrix, and her husband, Claus von Amsberg, and is the younger brother of the reigning Dutch king, Willem-Alexander. He is a member of the Dutch Royal House and currently fourth in the line of succession to the Dutch throne.
Prince Constantijn of the Netherlands is affiliated with the following schools: