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. Early on, the paintings typically depicted the Hudson River Valley and the surrounding area, including the Catskill, Adirondack, and White Mountains. Works by second-generation artists expanded to include other locales in New England, the Maritimes, the American West, and South America. The term Hudson River School is thought to have been coined by the New York Tribune art critic Clarence Cook or by landscape painter Homer Dodge Martin. It was initially used disparagingly, as the style had gone out of favor after the plein-air Barbizon School had come into vogue among American patrons and collectors. Hudson River School paintings reflect three themes of America in the 19th century: discovery, exploration, and settlement. They 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 which was 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 a reflection of God, though they varied in the depth of their religious conviction. They were inspired by European masters such as Claude Lorrain, John Constable, and J. M. W. Turner. Several painters were members of the Düsseldorf School of Painting, and they were educated by German Paul Weber. Thomas Cole is generally acknowledged as the founder of the School. He took a steamship up the Hudson in the autumn of 1825, stopping first at West Point then at Catskill landing. He hiked west high into the eastern Catskill Mountains of New York to paint the first landscapes of the area.