Calvinism, which he never shook off—to Shelley, in 1816, he described himself as ‘Methodist, Calvinist, Augustinian’—made him feel that his manner of life was wicked; but wickedness, he told himself, was a hereditary curse in his blood, an evil fate to which he was predestined by the Almighty. … Through her simplicity and her obliging good-nature, she became the means of providing him with the most delicious self-congratulatory remorse. He could feel himself the equal of the greatest sinners—the peer of Manfred, of Cain, almost of Satan himself.

Bertrand Russell, History of Western Philosop…, loc. 2713