Complex sentence: Between May 1839 and February 1840 "Fraser's" published the work sometimes considered Thackeray's first novel, "Catherine", originally intended as a satire of the Newgate school of crime fiction, though it ended up more as a rollicking picaresque tale.
Split into simpler sentences: Between May 1839 and February 1840 "Fraser's" published the work sometimes considered Thackeray's first novel, "Catherine". Originally intended as a satire of the Newgate school of crime fiction, it ended up being more of a rollicking picaresque tale.