After making films for several years, Warhol officially returned to painting in the early 1970s. He continued to use the silkscreen method but, rather than recreate the flat surfaces of the 1960s, now added expressive brushstrokes – the very gestural style he had rejected earlier in his career. In some of the larger works, these strokes would be added with a mop to simulate brushing the paint on by hand.
Warhol's portraits of Chairman Mao coincided with President Nixon's historic visit to Beijing. Like many of Warhol's subjects, the Communist leader was a contemporary icon. The official portrait used by Warhol appeared everywhere in China, while American radicals also knew it from the cover of the 'Little Red Book', an anthology of Mao's quotations. Warhol commented: 'I've been reading so much about China... The only picture they ever have is of Mao Zedong. It's great. It looks like a silkscreen.'
Warhol worked on numerous portraits at this time, painting contemporary icons, artists, collectors and friends, as well as taking on a large number of lucrative, commissioned portraits of society figures. The Skulls marked a counterpoint to this glamorous parade, what might even be seen as the final portrait. In some of the paintings, the shadow cast by the skull suggests the outlined head of a foetus, so juxtaposing the beginning of life with its end.