Mary Shelley was born Mary Wollstonecraft Godwin in Somers Town, London, in 1797. She was the second child of the feminist philosopher, educator, and writer Mary Wollstonecraft, and the first child of the philosopher, novelist, and journalist William Godwin. Mary’s maternal grandmother Elizabeth Dixon was born in Main Street Ballyshannon, Co. Donegal. Eleven days after Mary’s birth, her mother died of puerperal fever. Without a mother, Godwin immediately became the chief object of Mary’s affections. Mary Shelley's attachment to her father was to become intense and long lasting. Mary's favourite pastime as a child was to "write stories," and in 1808 her thirty-nine-quatrain reworking of Charles Dibdin's five-stanza song Mounseer Nongtongpaw was published by the Godwin Juvenile Library. This version became so popular that it was republished in 1830 in an edition illustrated by Robert Cruikshank.
In November 1812 at the age of 15, Mary met for the first time Godwin's new, young, and wealthy disciple, Percy Bysshe Shelley, and his wife, Harriet Westbrook Shelley. Percy Shelley shared Godwin's belief that the greatest justice is done when he who possesses money gives it to whomever has greatest need of it. Therefore it was not long before Shelley was supporting Godwin financially. When Mary next met the tall, frail-looking, elegant Percy, on 5 May 1814, she viewed him as a generous young idealist and as a budding genius. He, in turn, had become dissatisfied with his wife and was affected by Mary's beauty, her intellectual interests, and, above all, by her identity as the "daughter of William and Mary”. Inevitably, on 26th June, they declared their love for each other.
Upon discovering the relationship, Godwin, while still accepting Percy Shelley's money, forbade him from visiting the house. Mary tried to obey her father's injunction, but Percy's attempted suicide soon convinced Mary of the strength of his love, and on 28th July 1814 she fled with him to France. Mary gave birth to four children, only one of whom survived to adulthood. The first, a girl, was born prematurely and died eleven days later in 1815; William, born in 1816, died of malaria in 1819; Clara Everina, born in 1817, perished from dysentery the next year; Percy Florence, born in 1819, died in 1889. In 1822 Mary miscarried during her fifth pregnancy and nearly lost her life. Numerous critics have pointed out the link between the themes of creation, birth, and death in her gothic novel Frankenstein and Mary Shelley 's real-life preoccupation with pregnancy, labor, maternity, and death.
In 1815, shortly after the death of her first baby, Shelley recorded a dream that may or may not have had a direct influence on the plot of Frankenstein (1818). On 19th March 1815 she recorded in her journal: "Dream that my little baby came to life again--that it had only been cold & that we rubbed it before the fire & it lived." Her anxieties about motherhood and the inability to give life may have led her to write the tale of the aspiring scientist who succeeds in creating a being by unnatural methods. Shelley died on 1st February 1851 from a suspected brain tumour.