The Hudson River School was a mid-19th century American art movement embodied by a group of landscape painters whose aesthetic vision was influenced by romanticism. The paintings for which the movement is named depict the Hudson River Valley and the surrounding area, including the Catskill, Adirondack, and the White Mountains; eventually works by the second generation of artists associated with the school expanded to include other locales. Hudson River School paintings reflect three themes of America in the 19th century: discovery, exploration, and settlement. The paintings also depict the American landscape as a pastoral setting, where human beings and nature coexist peacefully. Hudson River School landscapes are characterized by their realistic, detailed, and sometimes idealized portrayal of nature, often juxtaposing peaceful agriculture and the remaining wilderness, fast disappearing from the Hudson Valley just as it was coming to be appreciated for its qualities of ruggedness and sublimity. In general, Hudson River School artists believed that nature in the form of the American landscape was an ineffable manifestation of God, though the artists varied in the depth of their religious conviction.