Was Beatrix illegitimate?
We see here on Leo's great website
http://www.genealogics.org/getperson.ph ... 6&tree=LEO
Guillaume I, Count of Sancerre who d 1217.
It there states that he married "after 1203" to Denise de Deols, dame
of Deols and Chateauroux
and yet shows Beatrix as their daughter.
Following down her line, Beatrix marries William I Count of Joigny who
d 1221
and they have a daughter Blanche who m firstly to Guillaume (William),
seigneur de Chateauroux
They marry "abt 1222" and their son William is born 1224 and William
(senior) dies 1234
The chronology is impossible unless one or more of these were born
before marriage and even then its probably impossible.
Any solution?
This connection is wrong, the family of Beatrix the second wife of Guillaume I of Joigny is unknown. She could not have been a daughter of Guillaum I of Sancerre due to the consanguinity that would result with her husband. This was pointed out by Edouard de Saint-Phalle in his study of the first dynasty of Joigny (1991).