Judith was the eldest daughter of the Frankish King and Holy Roman Emperor Charles the Bald and his wife Ermentrude of Orléans. She was born about 844. Judith inherited her name and her willful temperament from her grandmother, Judith of Bavaria. In 855 King Æthelwulf of Wessex made a to Rome, remaining there about a year. On his return in 856 he stayed at the court of the Holy Roman Emperor, Charles the Bald. In July Æthelwulf became engaged to Judith, Charles' oldest daughter. She was at most thirteen years of age at the time.