Bush's years in Berlin brought into his music the advanced Central European idioms that characterise his major orchestral compositions of the period: the Piano Concerto (1935–37), and the First Symphony (1939–40). Nancy Bush describes the Piano Concerto as Bush's first attempt to fuse his musical and political ideas. The symphony was even more overtly political, representing in its three movements greed (of the bourgeoisie), frustration (of the proletariat) and the final liberation of the latter, but not, according to Christiansen, "in an idiom calculated to appeal to the masses".