Alix was born about 1290. Alix's father was Gottfried Von Brabant-Aerschot and her mother was Jeanne De Vierson. Her paternal grandparents were Heinrich III der Friedfertige von Brabant and Alix de Bourgogne; her maternal grandparents were Herve III De Vierzon and Jeanne De Brenne. She had two sisters named Blanche and Isabella.