Bush's music, at least from the mid-1930s, often carried political overtones. His obituarist Rupert Christiansen writes that, as a principled Marxist, Bush "put the requirements of the revolutionary proletariat at the head of the composer's responsibilities", a choice which others, such as Tippett, chose not to make. However, Vaughan Williams thought that, despite Bush's oft-declared theories of the purposes of art and music, "when the inspiration comes over him he forgets all about this and remembers only the one eternal rule for all artists, 'To thine own self be true'."