Elements of a Gothic treatment of the South were first apparent during the ante- and post-bellum 19th century in the grotesques of Henry Clay Lewis and in the de-idealized representations of Mark Twain. The genre was consolidated, however, only in the 20th century, when dark romanticism, Southern humor, and the new literary naturalism merged in a new and powerful form of social critique. The thematic material was largely a reflection of the culture existing in the South following the collapse of the Confederacy as a consequence of the Civil War, which left a vacuum in its cultural and religious values. The resulting poverty and lingering bitterness over the issue of slavery in the region during Reconstruction exacerbated the racism, excessive violence, and religious extremism endemic to the region.