Matthew Lewis wrote his best-known work, The Monk, over a period of ten weeks at the age of 19. When first published there was public outcry against the violence and sexual content of the book, and in particular its blasphemy and covert homosexuality. The Marquis de Sade had high praise for it, calling it far superior in every respect to the strange flights of Mrs. Radcliffe's brilliant imagination. He may have recognized in it traces of his Justine, which Lewis obtained in Paris in 1792. Radcliffe's The Mysteries of Udolpho was another important influence. The Monk may have taken some of its content from the activities of the notorious Monks of Medmenham.
A previous attempt at a gothic story The Castle Spectre, inspired by Walpole's The Castle of Otranto, was later revised into a play.
When Lewis was elected to Parliament in 1796, it was to represent the seat of Hindon, vacated by William Beckford, author of Vathek. Beckford, although unprosecuted, was unable to take the seat because of outrage following the exposure of his liaison with Lord Courtenay. It is ironic that Lewis, whose homosexuality was hardly a secret, was accepted in his place. In fact, his association with deviance contributed to his celebrity.
In later years Lewis became infatuated with William Kelly, son of the gothic novelist Isabella Kelly. Lewis paid for Kelly's education and provided for him in his will, although it is not clear if the attraction was ever reciprocated.
Lewis met Goethe, author of The Sorrows of Young Werther in Weimar. Later when he visited the Villa Diodati in the summer of 1816, he brought a copy of Goethe's Faust which he translated to Byron, Polidori, and the Shelleys. There is some evidence in Frankenstein that he may have brought his copy of Justine also. The same year Lewis published his story Mina, which provided the namesake for Stoker's heroine in Dracula.
Like the Beckfords, Lewis owned a sugar plantation in Jamaica, the subject of his book Journal of a West Indian Proprietor. The year after visiting Byron he returned to Jamaica where he contracted yellow fever. Lewis died on the passage home and was buried at sea. The chain weights slipped off his coffin which bobbed back to the surface; when last seen, he was drifting back to Jamaica. In spite of his reservations about The Monk and Lewis' dinner parties full of young ensigns and mirrored bookcases, Byron wrote I would give many a Sugar Cane, Monk Lewis were alive again.