Empress Matilda

The Empress Matilda was the daughter and designated heir of Henry the First, and she should have been England's first reigning queen. Her father made his barons swear to accept her twice; they broke the oath the moment he died and crowned her cousin Stephen instead. She spent nineteen years fighting for the throne, was crowned at Winchester but never at Westminster, was driven out of London by a mob before the ceremony, and once escaped a besieged Oxford across the frozen Thames dressed in white against the snow. She never ruled, and she secured the succession for her son anyway. Through her this family descends from Henry the First by his legitimate line as well as by his natural son.