Wilhelmina's father formally announced her the successor to the throne in 1887. Her brother Prince Alexander had died in 1884.
There is even a theory that Alexander hadn't died, but was locked away, as a.o. father thought he wasn't suitable to be king.
Where was Prince Alexander locked away?
English wiki about Alexander: https://en.wikipedia.org/...exander,_Prince_of_Orange
. When reading the information among others on the Dutch wiki, I can only think that he was a bit of a tragic person. Since a young age he was sickly and nervous. For his mother, that was a reason to surround her dear Alex with the pet name Loulou, as she called him, with great care and love. This extra attention and care made him a mother's child, his father was annoyed by this.I think that his father was rather hars for Alexander (if it was the time spirit or just Willem IIIs charachter, I don't know) Also his parents had lost a son just before Alexander was born. His parents marriage was bad and there were a lot tensions. Unlike his eldest brother, Prince Alexander was disciplined, intellectual and read a lot.Alexander studied (Dutch) law at University in Leiden.In a short period of time he looses his beloved mother and his elder brother Willem. Alexander becomes more and more lonely. After the death of his brother Willem, Alexander feels even more lonely than he already was, after the death of his mother. He starts to think about marriage, he wants someone who understands him completely, with whom he can discuss his troubles and sorrows and where he can pour out his heart. Despite some plans and inquiries about suitable suitors, none of this will materialize.Prince Alexander eventually died unmarried and childless at the age of 32 on June 21, 1884 from typhoid fever. Because his father, who made a holiday trip to Germany and Switzerland with Queen Emma, his second wife, and their daughter Wilhelmina, did not intend to interrupt his stay there, the funeral was constantly postponed. The king did not return until July 15, 1884. Prince Alexander was interred on 17 July 1884 in the burial vault of the House of Orange in the Nieuwe Kerk in Delft. His half-sister Wilhelmina was the heir to the throne from his death. Others about Prince Alexander
> His mother, December 1876
: "My second son is an excellent person, but he has no charm for women, nor does he feel anything for them."
>Minister Weitzel, 20 May 1883, in his diary after a dinner with the prince
: 'I found the prince quite different from what I had imagined. ... He is a highly educated and highly entertaining man who speaks with knowledge and judgment about many matters and who listens with modesty or shrewdness to inquiries when topics come up that he is not sufficiently adept at. One can reason with him, he tolerates contradiction even if it is persisted to the utmost; he seems to be persuasive, although his actions do not always show it. He seems to lack the strength of mind to force himself; towards others, not least towards the King, he is persistent enough. "
> Once again an observation by the then Minister of War, A. Weitzel:
"In his statements he honors the principles of a very liberal constitutional monarch. He makes it very clear that he thinks he will apply those principles with scrupulousness, but has a policy of he no understanding. "
When Alexander lived on his own with his court, in the house on the Kneuterdijk in The Hague, Alexander had a broad interest in books and old writings, such as those of Voltaire and other intellectuals, from which he collected original manuscripts and other important pieces from the time. of the Duke Alva and the struggle for independence in the Southern Netherlands in the 1830s. He also started collecting butterflies and miniatures, making his house a kind of cabinet of curiosities. The underlying thought was that he tried to seek distraction - and after the death of his mother and brother Prince Willem - in these worldly matters. Painting also pleased him and he built up a collection of paintings and encouraged young artists and even paid for their education in some cases. Visual arts institutions can always count on Alexander's support.
However, he has not completely isolated himself from the outside world, but keeps himself informed through newspapers and other sources about what is happening around him.
During the last years of his life he bought a number of things that had been the property of his late mother and brother. These had been offered for sale by King Willem III, one of these things was the former home of his brother Willem, Paleis Kneuterdijk. He knows how to buy back this house from the municipality of The Hague, because he believes that this house should remain in the family. He also managed to buy back a precious pearl necklace from his deceased mother from a jeweler to which King William III had sold it.
In his later life the bond between Alexander and his father deteriorated. The remarriage of his father and the mutual misunderstanding, due to extremes in characters, made him lead a secluded life in the years before his death.
Since Alexander did not have a will, after his death, his possessions were sold through a public auction. His father was not interested in any of this. He does refrain from selling jewelry that had been owned by his first wife Sophie, so as not to hurt the feelings of many. The estate includes a pile of letters and documents, some of which come from Queen Sophie. For reasons of privacy, these are entrusted to Alexander's personal secretary, Willem Johannes Dominicus van Dijck, who, at the request of Queen Emma, would keep them in his family until 1924, 40 years after the death of the Crown Prince. These documents were later returned in a solid box by the grandson of the personal secretary Van Dijck, then reigning Prince Queen Wilhelmina.
The complot theory does not define the exact location, but it was thought Alexander was put in an Asylum.
In the '90s there is been a Dutch tv show that has a play with this complot theory. It was called "Wij Alexander" (We Alexander) and goes about a new doctor in an asylum who meets a patient who claims to be Prince Alexander.....
Here you can see some parts of this Dutch series: https://tvblik.nl/wij-alexander/16-juni-2020
The very short English wiki about the series: https://en.wikipedia.org/wiki/Wij,_Alexander
Translation of the story line of the series:"...The main character in the series is Prince Alexander. He lived from 1851 to 1884 and was the third son of King Willem III and his first wife Princess Sophie of Württemberg. Alexanders oldest brother, Willem, was always gone and attended all kinds of boarding schools. His brother Maurits had already died in 1850 at the age of seven, before Alexander's birth. Alexander soon became his mother's favorite. He was very sick from childhood and according to some he would have had a weak character.
The series begins in 1909, one day after the birth of Princess Juliana. The Netherlands is celebrating because the monarchy has been secured with Juliana's birth. Psychiatry student Jan Giltay (played by Hugo Haenen) starts working in a clinic around the same time. There he becomes intrigued by patient no. 4 (played by Jacques Commandeur). He claims to be Prince Alexander, who already died in 1884. Doubt arises because the patient knows a lot about life at court. This life is shown in flashbacks and is based in part on facts. These flashbacks form a second storyline in the series. In it we see, among other things, the bad marriage of King Willem III and Sophie and the struggle for the children.
Jan Giltay is very passionate about treating patient no. 4. Then he receives information that indicates that the patient may really be Crown Prince Alexander. Giltay is ordered to treat the "prince" and to gather information about a secret box belonging to the crown prince, in which the prince allegedly collected incriminating evidence against his father. From this information it would appear that Queen Wilhelmina cannot be a daughter of William III.
The story develops into a thriller-like plot, in which blackmail and murder lead to the psychiatrist and his patient fleeing to Paris. The answer to the key question in Wij Alexander, who is patient No. 4 really, is slowly revealed as the story progresses. In addition, various parties are looking for the box...."