Historians have divided the history of Cubism into phases. In one scheme, the first phase of Cubism, known as Analytic Cubism, a phrase coined by Juan Gris a posteriori, was both radical and influential as a short but highly significant art movement between 1910 and 1912 in France. A second phase, Synthetic Cubism, remained vital until around 1919, when the Surrealist movement gained popularity. English art historian Douglas Cooper proposed another scheme, describing three phases of Cubism in his book, The Cubist Epoch. According to Cooper there was "Early Cubism", (from 1906 to 1908) when the movement was initially developed in the studios of Picasso and Braque; the second phase being called "High Cubism", (from 1909 to 1914) during which time Juan Gris emerged as an important exponent (after 1911); and finally Cooper referred to "Late Cubism" (from 1914 to 1921) as the last phase of Cubism as a radical avant-garde movement. Douglas Cooper's restrictive use of these terms to distinguish the work of Braque, Picasso, Gris (from 1911) and Léger (to a lesser extent) implied an intentional value judgement.