Mathilde was added to the tree as a sister of Simon II von Salm.
Simon's parents were married around 1355 and his birth date is estimated around that time as are his brothers and sisters.
Mathilde is born 36 years later in 1391.
We do not have an exact date for Simon II's marriage but as he married a widow it must have been 1391 or later (the year her previous husband died).
Is it possible that Mathilde is actually Simon II's daughter not his sister?