Men of Letters (The Winchesters)
The Men of Letters is a secret organization of scholars who researched the supernatural. The order has been in existence for centuries, during which they helped to thwart the invasion of their universe from the Akrida.
The Men of Letters Massacre of 1957
The Men of Letters were destroyed in 1957 by former hunter Joan Hopkins who had taken to consuming the essences of monsters, which led to her banishment by the Men of Letters. However, Joan's banishment sent her to the world of the Akrida-- creatures created by God to act as a "failsafe" to destroy all of creation if he were to ever be bested.
During an attempted incursion in 1957, the Men of Letters were successful in keeping the Akrida from invading. However, Joan Hopkins was able to kill the Men of Letters by using the last of her strength, which left her in a weakened state, and forced her into hiding.