Who challenged Mary shelly to write a ghost story?

Mary Shelley was challenged to write a ghost story by Lord Byron, along with Percy Shelley and John Polidori.

The challenge occurred during a trip to Switzerland in 1816, during a period of bad weather that forced them to stay indoors. To pass the time, the group decided to hold a contest to see who could write the best ghost story. This led to the creation of several famous works, including Mary Shelley's *Frankenstein* and John Polidori's *The Vampyre*.