Erasmus Darwin, grandfather of Charles Darwin, was best known for the poetry in which he expressed his scientific ideas. The leading medical man of his day, he was asked several times to be personal physician to King George but declined. Darwin was a Radical and had ethical objections to the existence of a monarchy. Intellectual, inventor, and free-thinker, he had many learned friends including Richard Lovell Edgeworth, Dr. Thomas Beddoes, Henry Fuseli, Benjamin Franklin, and Josiah Wedgwood, Charles Darwin's other grandfather (see Mary Wollstonecraft). All of these men were members of or had connections with the Lunar Society, a Birmingham-based group of radical intellectuals who met once a month when the moon was full (to facilitate night travelling). It may be in joking reference to them that the first vampires were called Lunarians ostensibly because the full moon had power to revive them from the dead.

Darwin was also acquainted with the Godwin family and his experiments with primitive life forms (at least as perceived and discussed at the Villa Diodati,) were a key factor in inspiring Mary Godwin 's dream, which in turn provided the spark for Frankenstein.

Although the devout S.T. Coleridge deplored Darwin's atheism and evolutionary theories, he admitted Dr. Darwin possesses, perhaps a greater range of knowledge than any other man in Europe and is the most inventive of philosophical men. He thinks in a new train on all subjects except religion...When he talks on any other subject he is a wonderfully entertaining and instructive old man...... I absolutely nauseate Darwin's Poem. Nevertheless, he was a considerable influence on Coleridge's Theory of Life.

Darwin's poetry influenced Keats, Shelley, Byron, Wordsworth and (the grudging) Coleridge.