Mary was born in 1797, in London, England. She was the daughter of philosopher and political writer William Godwin and Mary Wollstonecraft, an early feminist author who died when Mary was still young. Godwin married again and children were added to the household.
Despite being a member of an extended family, Mary was a lonely child. Uneducated, she nevertheless read widely. In 1814, Mary began a romantic relationship with Percy Shelley, an anarchist poet. Together with Mary's stepsister, Claire Clairmont, they left for France and travelled through Europe. Upon their return to England, Mary was pregnant with Percy's child. They married in late 1816 after the suicide of Shelley's first wife, Harriet.
In 1816, the couple famously spent a summer with Lord Byron, Dr. Polidori and Claire in Lausanne. It was here that Mary conceived the idea for her famous novel. It is surprising that at the age of nineteen she produced such a mature work as Frankenstein.
Widowed after six years of marriage, Mary lived until 1851.