August 24th is associated with the apostle St. Bartholomew, who was flayed alive while on mission in Armenia. The feast of St. Bartholomew's day appears in several of Scott's novel's, including Kenilworth, Peveril of the Peak, and Quentin Durward. St. Bartholomew's symbol is the knife, in remembrance of Bartholomew's horrible death. It is an ill portent, when the day appears in Scott's stories.
There was also the St. Bartholomew's Day Massacre, which began on 8/24/1572. The initial violence occurred in Paris, where Catholic (Queen Mother) Catherine de Medici's daughter Marguerite was to be married to Huguenot Prince Henry of Navarre. Thousands of Huguenots were killed (est. 8k - 20k) in the on-going slaughter, which persisted into September of that year.