The four were
江青 (Mao's wife),
张春桥,
姚文元 and
王洪文. Less than a month after Mao died, on 6 October 1976,
华国锋 and
叶剑英 had them arrested, and a trial in 1980 sentenced them to long prison terms or death with reprieve. The name goes back to Mao himself, who in the mid-1970s warned them not to act as a gang of four.