THE SUMMER OF 1816

Mount Tambora erupted in April 1815 with such violence that it threw enough ash into the atmosphere to darken the sun across the Northern Hemisphere. Europe shivered through what came to be known as "the year without a summer." Crops failed. Livestock died. And in Switzerland, on the shores of Lake Geneva, it rained.

At the Villa Diodati on the lake's shore, a group of young people was trapped indoors. Lord Byron had rented the villa—the most famous poet in Europe, beautiful and scandalous. With him was his personal physician, John Polidori, age 20, whose literary ambitions exceeded his medical judgment. Nearby, in a more modest cottage, Percy Bysshe Shelley kept house. At 23, he'd abandoned his pregnant wife to elope with Mary Godwin, the 18-year-old daughter of two of England's most famous intellectuals. Mary's stepsister Claire completed the party. She was pregnant with Byron's child.

The domestic arrangements were unconventional. None of them was older than 28.

Byron proposed a competition. They'd been reading ghost stories, Gothic tales from Germany full of supernatural terrors. "We will each write a ghost story," he announced.

Byron began a fragment about a vampire. Shelley started something, lost interest, abandoned it. Polidori took Byron's vampire idea and eventually produced "The Vampyre," a story that would launch the vampire genre in English literature, though it would be attributed to Byron for years. Polidori never did have much luck.

Mary struggled. For days, she had nothing. The others had moved on, forgotten the challenge entirely. She couldn't let it go.

Then one night it came to her—a waking dream, a vision of what she called "the pale student of unhallowed arts" kneeling beside the creature he'd assembled, watching with horror as it stirred to life. The image terrified her. She opened her eyes to escape it.

But then she recognized what she had. "I have found it!" she thought. "What terrified me will terrify others."

The next day she began writing. Percy urged her to expand it into a novel. By the time she was 19, she'd completed Frankenstein; or, The Modern Prometheus.

The unnatural cold created an atmosphere of dread, as if the world itself were coming undone. The intellectual intensity of the group fed her imagination—they talked endlessly about galvanism, about whether electricity could animate dead tissue, about whether the principle of life itself could be discovered and controlled. Percy and Byron, both brilliant, both optimistic about human progress, saw science as liberation.

Mary saw hubris. Her mother died giving birth to her. Her first baby died unnamed, not yet two weeks old. She understood the fragility of life and the presumption of trying to control it.

She was a young woman in 1816. Young women weren't supposed to write about science and ambition, about obsession. But no one expected anything from Mary Godwin. Perhaps that gave her freedom.

When Frankenstein appeared in January 1818, it was published anonymously. Percy wrote the preface. Many assumed he was the author. Even when Mary's authorship became known, critics struggled to believe that this extraordinary novel had been written by a woman barely out of her teens.

Byron's vampire fragment went unfinished. Polidori's "The Vampyre" had brief success, then faded. Percy's abandoned effort left no trace. Mary's monster lived on.

That summer at the Villa Diodati, five young people thought they were amusing themselves during bad weather. Mary Shelley was 18 years old. She'd buried one child. Three more would die before her own death. She would be widowed at 24. She would spend most of her life in poverty, struggling to support herself through writing. That summer, though, she created something that would not die.

MARY SHELLEY - BIOGRAPHY

Mary Shelley created one of the most enduring works of literature at age 18, virtually inventing the science fiction genre. Despite personal tragedies that would have crushed most people—losing her mother at birth, three of her four children, and her husband by age 25—she persevered as a writer and intellectual. She challenged the boundaries of what women could achieve in literature and left an indelible mark on world culture. "Frankenstein" has never been out of print since 1818 and remains one of the most adapted and referenced works in human history.

1797 — Born Mary Wollstonecraft Godwin on August 30 in London. Her mother, the pioneering feminist writer Mary Wollstonecraft, dies eleven days later from complications of childbirth. Her father is the philosopher and novelist William Godwin.

1801 — William Godwin marries Mary Jane Clairmont, who brings two children into the household. Young Mary's relationship with her stepmother is difficult throughout her childhood.

1812 — At age 14, Mary is sent to Scotland to live with the Baxter family for her health and to escape tensions at home. She spends two formative years there, developing her imagination in the Scottish landscape.

1814 — At age 16, Mary meets the married Romantic poet Percy Bysshe Shelley, a disciple of her father's radical philosophy. They fall in love and, on July 28, elope to France, accompanied by Mary's stepsister Claire Clairmont. William Godwin is outraged and refuses to see them.

1815 — Mary gives birth to a premature daughter in February, who dies within two weeks. The loss devastates her. She writes in her journal: "Dream that my little baby came to life again."

1816 — Mary gives birth to a son, William, in January. In May, the Shelleys travel to Switzerland to spend the summer near Lord Byron at the Villa Diodati on Lake Geneva. During a stormy night in June, Byron proposes that each person write a ghost story. Mary begins "Frankenstein." Percy's wife, Harriet, drowns herself in December. Percy and Mary marry on December 30.

1817 — Mary gives birth to a daughter, Clara, in September. She completes "Frankenstein" and submits it for publication. The family faces financial difficulties and social ostracism.

1818 — "Frankenstein; or, The Modern Prometheus" is published anonymously on January 1. Many assume Percy Shelley wrote it. The Shelleys move to Italy in March, hoping the climate will improve Percy's health.

1818 — Clara dies in September at age one, likely from dysentery. Mary is devastated and blames Percy for insisting they travel while the baby was ill.

1819 — William, Mary's beloved three-year-old son, dies of malaria in June. Mary falls into severe depression. She gives birth to another son, Percy Florence, in November—her only child who will survive to adulthood.

1820-1822 — Mary writes and studies while living in Italy. She suffers a life-threatening miscarriage in 1822 that nearly kills her. Percy saves her life by having her sit in a bath of ice.

1822 — Percy Bysshe Shelley drowns on July 8 when his boat sinks during a storm in the Gulf of La Spezia. He is 29 years old. Mary is 24, widowed with a young son, and faced with financial insecurity.

1823 — Mary returns to England with her son. She begins her career as a professional writer to support herself and Percy Florence. She negotiates with her hostile father-in-law, Sir Timothy Shelley, who provides a small allowance on the condition that she not publish a biography of Percy.

1826 — Publishes "The Last Man," a post-apocalyptic novel set in the 21st century, considered one of the first modern science fiction works about the end of humanity.

1835-1839 — Writes biographical entries for "Lives of the Most Eminent Literary and Scientific Men" for Lardner's Cabinet Cyclopedia, producing insightful essays on European writers.

1838 — Publishes "Falkner," her last novel.

1839 — Edits and publishes "The Poetical Works of Percy Bysshe Shelley," finally able to honor her late husband's literary legacy after Sir Timothy's death. Her extensive notes transform how Percy's poetry is understood.

1840-1844 — Travels extensively in Europe with her son, who attends Cambridge University. She continues to write stories and essays but faces declining health.

1848 — Percy Florence inherits the Shelley baronetcy and estate, finally providing Mary with financial security after decades of struggle.

1851 — Mary Shelley dies on February 1 at age 53, likely from a brain tumor. She is buried in St. Peter's Church, Bournemouth, alongside her parents' remains. After her death, a copy of Percy's poem "Adonais" is found in her desk drawer, containing the ashes of his heart, which she had kept for 29 years.