Secrets of history: Catherine De' Medici

Catherine de’ Medici was an Italian noblewoman who was Queen of France from 1547 until 1559, as the wife of King Henry II. His death thrust her into the political arena as Queen Mother and Regent from 1560 to 1564. A legend, dating back to the time of the religious wars, has followed her for centuries. The murky role she played in the St. Bartholomew's Day massacre continues to divide scholars. In the Loire Valley, the castles she lived in reveal their secrets.