In April 1815, the eruption of Mount Tambora—one of the largest volcanic eruptions ever recorded—decimated the Indonesian island of Sumbawa. The blast reached the stratosphere, sending plumes of ash and sulfur across the entire world. Global temperatures plummeted as particles in the air obscured the sun, ushering in a volcanic winter. This lasted well into 1816, now known as the “Year Without a Summer.”

So, what does all that have to do with Frankenstein? A lot, actually.

In June 1816, Mary W. Shelley (then Mary Godwin), Percy Bysshe Shelley, and Mary’s stepsister Claire Clairmont traveled to Switzerland where they visited the poet Lord Byron. The latter was staying at a villa on Lake Geneva with his friend and personal doctor, John Polidori. The group wanted to spend their time outside by the water, but the unseasonably cold and rainy weather—caused by the Mount Tambora eruption—spoiled their plans. Mary mentions this in her 1831 preface to Frankenstein, saying it was “a wet, ungenial summer, and incessant rain often confined [them] for days to the house.”

Stuck indoors, they turned to books. After reading Fantasmagoriana, an anthology of supernatural tales, Byron challenged his guests to each write a ghost story. While the others got to work, Mary struggled to come up with an idea.

In the meantime, she listened to Percy and Byron’s many conversations about literature, science, and philosophy. One discussion centered around galvanism, a concept that proposed electricity could stimulate or restart life. Mary wondered if corpses could be reanimated, or if “a creature might be manufactured, brought together, and endued with vital warmth” through this type of phenomenon.

Later that night, in the early hours of June 16, 1816, Mary was struck with a powerful vision. She wrote:

“When I placed my head on my pillow, I did not sleep, nor could I be said to think. My imagination, unbidden, possessed and guided me, gifting the successive images that arose in my mind with a vividness far beyond the usual bounds of reverie … I saw the pale student of unhallowed arts kneeling beside the thing he had put together. I saw the hideous phantasm of a man stretched out, and then, on the working of some powerful engine, show signs of life, and stir with an uneasy, half vital motion.”

This “waking dream,” as Mary called it, “possessed [her] mind.” She couldn't forget the imagery of a man watching his creation come to life, first awed by his success, then horrified that the creature continued to move. The man tries to sleep, believing that the “slight spark of life which he had communicated would fade” and the creature would die. But he wakes to see the thing standing by his bed, peering down at him.

Though frightened by her dream, Mary was excited. She finally had a ghost story to tell. The next day, she began working on a rough transcript, starting with the now famous line, “It was on a dreary night of November…” At first, she envisioned it as a short story, but after Percy read what she wrote, he encouraged her to turn her ghost story into a novel.

Soon, the extraordinary summer of 1816 faded away, and the Geneva trip came to an end. Over the next year, Mary continued to write, eventually completing the work in spring 1817. Her novel, Frankenstein; or, The Modern Prometheus, was published in January 1818 anonymously. In later editions, Mary was credited as the author.

Today, Frankenstein remains one of the most important and influential literary works in history. With its emphasis on intense human emotions, nature, and individuality, it is a hallmark of Romantic and Gothic literature. Centuries ago, had the weather been warmer, had it not rained those days in June, we may never have known such a profound story.

Resources for Teaching Mary Shelley’s Frankenstein