Answer
The St. Bartholomew's Day massacre, witnessed by Walsingham during his ambassadorship in France, was a horrific event that occurred in 1572. It was a premeditated and organized attack on the Huguenots, a religious minority group in France, carried out by Catholic extremists with the involvement of the French monarchy. Thousands of Huguenots were brutally killed in Paris and other parts of France, marking a dark chapter in French history.