In 1686, just as Newton was preparing for the publication of the Principia , the Historia Piscium was being printed under the auspices of The Royal Society. The Historia Piscium was a work begun by Francis Willughby (1635–1672, F.R.S. 1663), completed by John Ray (1627–1705, F.R.S. 1667) and brought into print with the financial support of The Royal Society. The text and illustrations of the Historia Piscium reflect the 17th-century origins of the enterprise: Ray's quest to recover the knowledge and language lost in the Fall, and The Royal Society's support for establishing a reformed natural history of fish through publication. Ray's biblical belief in the corruption of human language and knowledge led him to reform natural history through ‘characteristic marks’. He sought to define, classify and depict fishes through their external features, which when matched up, would yield the same nature, and thus allow humans to identify and give a name to a fish. The Royal Society helped Ray's task by confirming the validity or uselessness of a given author on the subject, suggesting other authorities and sources for illustrations, organizing the printing, checking the corrections and paying for the cost of the printing. Subscriptions were sought for the illustrations and the inscriptions of subscribers reflect the Society's concern to promote its institutional identity and its supporters. Some Fellows of the Society also helped Ray with identities and classification of fishes, and changes were made in response to suggestions and objections of other Fellows. Without the intellectual and financial support of the Society, especially Pepys, Lister and Robinson, the Historia Piscium would not have been published in the way that it was. Despite the subscription, however, the Historia Piscium was a costly venture, largely due to its lavish illustrations, and the subsequent flop of sales of the book meant that The Royal Society faced serious financial problems. This is perhaps the main reason why it could not meet the cost of publishing Newton's Principia .