The Emperor Who Kneeled in the Snow: How a Noblewoman Changed the Course of Medieval Europe January 1077. Emperor Henry IV, the most powerful man in Europe, stood barefoot in the snow outside Canossa Castle for three days. Inside, Matilda of Tuscany looked down from her fortress as the ruler of the Holy Roman Empire humbled himself, seeking forgiveness from Pope Gregory VII who was under her protection. This wasnt just her castle it was her domain. As Margravine of Tuscany, Matilda ruled over va