The increase in secular literature at this time encouraged the spread of lending libraries, especially the commercial subscription libraries. Commercial subscription libraries began when booksellers began renting out extra copies of books in the mid-18th century. Steven Fischer estimates that in 1790, there were "about six hundred rental and lending libraries, with a clientele of some fifty thousand". The mid- to late 18th century saw a virtual epidemic of feminine reading as novels became more and more popular. Novels, while frowned upon in society, were extremely popular. In England there were many who lamented at the "villanous profane and obscene books" and the opposition to the circulating library, on moral grounds, persisted well into the 19th century. Still, many establishments must have circulated many times the number of novels as of any other genre.