Ermengarde de Tonnerre, Ctss de Tonnerre

https://www.findagrave.com/memorial/111188632/ermengarde_nevers

ERMENGARDE de Tonnerre (c1023/26 - <1090) Ctss de Tonnerre
d/o RAINARD de Tonnerre (c980/90- >16 Jul 1039) & HELVIS (->16 Jul 1039)
x c 1039 GUILLAUME I Comte de Nevers et d'Auxerre, (s/o RENAUD I Comte de Nevers & Hedwig)

• RENAUD [II] de Nevers (-killed 5 Aug 1089)
• GUILLAUME [II] de Nevers (->1099) Comte de Tonnerre
• ROBERT de Nevers (-12 Feb 1095, bur Nevers Saint-Etienne) Bishop of Auxerre 1076/1084.
• ERMENGARDE de Nevers (-c14 Oct 1090/1095)
• HELVISE de Nevers (-cFeb 1113/18 Apr 1118, bur Noyon)

https://fmg.ac/Projects/MedLands/burgdtonne.htm#MiloIVTonnerredied1...
https://fmg.ac/Projects/MedLands/burgdnevers.htm#GuillaumeINeversdi...

Hugues-Renaud was named Count of Tonnerre and Bar-sur-Seine after his mother Azeka died. When he chose to become a priest, he ceded his title to Tonnerre to his cousin Ermengarde de Tonnerre, wife of Guillaume I de Nevers, count of Nevers and Auxerre. He ceded his title of Count of Bar-sur-Seine to his sister Eustachie de Tonnerre and her husband Gautier I de Brienne, Count of Brienne.

See https://fr.wikipedia.org/wiki/Ermengarde_de_Tonnerre

She was living between 1036 and 1089 [Roderick W. Stuart, Royalty for Commoners: The Complete Lineage of John of Gaunt, Son of Edward III, Kings of England, and Queen Philippa (.: ., 3rd Ed., 1998), 254-32].