 Although environmental aesthetics has developed as a sub-field of Western philosophical aesthetics only in the last forty years, it has historical roots in eighteenth and nineteenth century European and North American aesthetics. In these centuries, there were important advances in the aesthetics of nature, including the emergence of the concept of disinterestedness together with those of the sublime and the picturesque, as well as the introduction of the idea of positive aesthetics. These notions continue to play a role in contemporary work in environmental aesthetics, especially in the context of its relationship to environmentalism. (See also Section 5.1 below.)