 Church's landscape conformed to the aesthetic principles of the "picturesque", as propounded by the British theorist William Gilpin, which began with a careful observation of nature enhanced by particular notions about composition and harmony.The juxtaposition of smooth and irregular forms was an important principle, and is represented in "The Heart of the Andes" by the rounded hills and pool of water on the one hand, and by the contrasting jagged mountains and rough trees on the other.The theory of British critic John Ruskin was also an important influence on Church.