Originally Posted by CyrilVladisla
Prince Bernhard registered his son's birth in 1967. In the following video Prince Bernhard said that the child will be called Alexander.
What confuses me is that if he is called Alexander
where did Willem
You are obviously confused; as it was Willem-Alexander's father Claus not his grandfather Bernhard who registered his son's birth
His official name is Willem-Alexander (a very logical choice given that the Netherlands had only had kings named 'Willem'); but the name they would use in daily life would be Alexander. It is quite common in the Netherlands that your official name is different from the name that is used in daily life. And it is also common to announce that on the birth announcement send to family and friends (for example by putting the 'calling name' on the front and the full name inside - the 'calling name' might be the same as the first name but could be different as well). In this case, the second part of the official first name is the one that is used among family and friends.
So, his official name was: Willem-Alexander Claus George Ferdinand (to be called: Alexander).
Willem-Alexander and Máxima did the same with Amalia.
Her official name is: Catharina-Amalia Beatrix Carmen Victoria (to be called: Amalia)