Illegitimate Child of King Leopold II of Belgium ?

Who are Mary's Parents? Here are the clues I  have on her:
Mary 'Tyvaert' was born 10 April 1880 in Germany. Her real surname is NOT 'Tyvaert'.  Her Baptized name is apparently (read full story below) Caroline (could be spelled: Karoline) Marie Von Altenburg..but since Mary's grandmother didn't want to take care of a 'bastard' child, she gave her to a family to be adopted, read the whole story below:

Her mother was a 19 year old Countess who had a liaison with someone in Belgian Royalty. We know that 8 or 9 days after giving birth to 'Mary', she died. And the secret was suppose to stay a secret. After she died, 'Mary's' grandmother gave her to Coleta Vanthuyne (another spelling of the surname: VanThuine . She was married to Bruno Tyvaert)

 Here background story-by one of her 'nieces' from her adoptive family. This is the email that I got from a family member of Mary's adoptive side of the family years ago:
This was emailed to me several years ago by a family member (not related by blood, related by Mary's adoptive family) :

Here is the story:
Sylvia Van Thomme Evans wrote a story shortly before she died because she wanted to share this with future generations. This story was supposed to be kept a secret and most of the Tyvaert (Tivaert) and Van Thomme family doesn't know about it.
But here it goes:
Two uncles of Sylvia's came to America from Belgium to get a new start and find jobs. The uncles were Henricus Tyvaert and Desiderius Tyvaert. They found jobs at the Packard Auto Planet and saved up their money and found a place near St. Charles Church in Detroit, Michigan. Later they sent for their mother, Coletta Vanthuyne - Tyvaert  and sisters, Lucia and Pauline.
The family did not have a lot of money and the brothers, Henry and Desiderius had a hard time obtaining the funds for their mother and sisters. In the meantime their mother, Coleta made an acquaintance with a woman who had a problem... I am not sure if this was in Gent, Bruge or Brussels.. but I know that the woman who had a problem told Coletta (Coleta) that she had a daughter, approx. 19 years in age had given birth out of wedlock. She said she would pay for their passage to America if they would take the baby and adopt her.
The baby became known as Mary Tyvaert b. 10 April 1880

A clue that I received via email a few years ago was her father was indeed King Leopold II of Belgium. Everyone who knows Belgian Royal history is that Leopold II was known to have 'lovers' during his lifetime and he only claimed his male illegitimate children. The male illegitimate children are well-known. As for any other illegitimate children he had, most have been kept a 'secret'; a secret that was suppose to be forgotten.

Another clue was an email sent to me back in 2004, a fellow genealogist said she found information on my great-great-great grandmother, that her name was Caroline Marie Von Altenburg. And her mother was Charlotte Von Altenburg, a Countess. So she was nobility and it said that her father was King Leopold II.
Here is the email:
Charlotte Charlotte Von Altenburg and the child is a parish Register entry dated 10 April 1800 from St. Catherine's Church, Burg Altena, Westphalia, Germany. Because the child was born out of wedlock, the child was baptized and the parents given in the register.
However, the mother died and her death is also recorded and note of her adoption and removal to America is noted by the parish priest.

So if this is true, that means there are documents in Germany or the fellow genealogist knows where they are located.

So the question remains, who were Mary's parents? If it was indeed Charlotte Von Altenburg who sadly died 8 or 9 days after the birth of Caroline (Karoline) Marie Von Altenburg and Charlotte was one of King Leopold II's many 'one time lovers' then knowing the truth puts me at peace.
Fyi, it was rumored that Charlotte was buried in an 'unmarked' grave after she died.