In London, Dyer apprenticed himself under the artist Jonathan Richardson. Richardson's fundamental principle of painting was that all aspects of learning, from reading, observation of nature, studying works by masters in painting and writing poetry were necessary to provide artists with inspiration. As a result, Dyer retained such interests and translated his studies into verbal landscape art. His first attempt in writing Miltonic octosyllabic couplets was addressed to his mentor, "An Epistle to a Famous Painter", the same measure as in his second version of "Grongar Hill". It was under Richardson that Dyer met his coffee house group of friends, Thomas Edwards, Daniel Wray, George Knapton and Arthur Pond. Pond would later be referred to in "The Fleece" (IV. 265).