Though politics have influenced the visual arts throughout history in many and different ways, most notably under the Ancient Roman Empire and during the revolutionary and courter revolutionary years of the nineteenth century, then have seldom played so prominent a role as they did during the 1920s and 1930s. Relations between Communism and the arts were close, though they followed a zigzag course both in Russia and in western Europe (see pp.819-21) ; Fascism and Nazism were also actively concerned with art as propaganda; and the period closed with one of Picasso’s major works which is also his only explicitly political painting (20.49). However, it was in Mexico that the relationship between politics and art during these years was most fruitful, partly because the Mexican artists themselves formulate much of the theoretical base on which their program for a new public art was erected, and partly because it was combined with the quest to rediscover their national identity. By the time Rivera painted his The Making of a Fresco, showing the Building of a City (20.14) the revolutionary fervour of his early years had relaxed, but it continued to inform all his work and it is in this context that his paintings and also those of his sometime companions Jose Clemente Orozco (1883-1949) and David Alfaro Siqueiros (1894-1974) should be seen.