Wikipedia
Thelchildes
Saint Thelchildis, was abbess of Jouarre Abbey and mentor of Berthild of Chelles. She remained Abbess at Jouarre until her death in 660 660 AD.
When Saint Bathildis, the wife of Clovis II, founded the Abbey of Chelles, she asked Saint Thelchildis to oversee the foundation, and to pick "the most experienced and virtuous nuns of Jouarre" to join her. She appointed St. Bertilde of Chelle as first abbess, about 646.
She was the mentor of both St. Bertilde, Abbess of Chelles, and St. Etheria, first Abbess of Notre-Dame of Soissons (658).