Isabella’s parents were Baldwin V of Hainaut and Margaret I of Flanders. Her maternal uncle, Phillip of Flanders, then advisor to Phillip Augustus, made arrangements with her parents for her to marry the king. They were wed in 1180, with Isabella bringing Artois as her dowry. She was crowned Queen of France at the age of ten.
Four years later, when she was fourteen, Phillip decided to repudiate her and marry someone else. He had two major reasons for this. First, her father supported the county of Flanders in its war against him. Second, she, a fourteen year old, had not yet given him a male heir. Isabella knew she had to act and knew that in doing so she could use the favor the populace. She went out into the streets of Sens, where they were staying, dressed as a penitent, barefoot and in only a shift, begging for mercy, shaming him for trying to get rid of her. The people of the town rose in her favor.
It was this action and her uncle’s reminder that if Phillip repudiated her, he would lose Artois as well that saved her position as Queen. She finally did have a son in 1187, the future Louis VIII and husband of Blanche of Castile. She died only three years later at the age of 19, from complications related to childbirth.
*With her brother Baldwin’s inheritance of Hainaut from their father and Flanders from their mother (who inherited the title after her own brother died childless a year after Isabella’s death), the two counties were ruled together. They would be separated again a few generations later, divided between the Avesnes and Dampierre sons of Marguerite.