When Mathilde was eight, Victoire tried to run away from home, only to be caught by Mathilde.
When the two women were older, they parted ways. Mathilde stayed at the family home to make cheese the hands-on way, while Victoire went to Paris and used science and chemicals. Some of Victoire's cultures were stolen, and the Seventh Doctor and Inspector Toprak visited Mathilde to see if she had stolen them. She had stolen them, hoping to make a cheese that was immune to disease. (PROSE: Culture War)