A quote from Samuel Taylor Coleridge's darkly allegorical Rime of the Ancient Mariner; the tale of a wizened seafarer, whose voyage into the unknown regions of the Antarctic leaves him with a unique insight into the secrets of nature, and a heavy burden of guilt for disturbing them. Coleridge was among the literary men who had visited Mary Shelley's father William Godwin when she was a young girl and, although quoted directly only twice, the poem's influence runs throughout Frankenstein.
Coleridge's chief contribution to his and Wordsworth's seminal anthology Lyrical Ballads (1798), the poem fulfils his goal of heightening the depiction of supernatural situations by maintaining "the dramatic truth of such emotions, as would naturally accompany such situations, supposing them real". This ambition is echoed in the preface to Frankenstein, which sets out the novel's intention "to preserve the truth of the elementary principles of human nature" despite its fantastical subject matter.
Online edition of Samuel Taylor Coleridge's 'Rime of the Ancient Mariner', (D. Appleton & Co., 1866)