Updated

The indictment of China's former security boss Zhou Yongkang marks the latest chapter in the Communist Party's history of purging itself of leaders who've fallen out of favor politically or whose alleged crimes appear too serious to go unnoticed.

Zhou is charged with corruption and the leaking of state secrets. As a former member of the party's all-power Politburo Standing Committee, he would be the highest-ranking Chinese official, sitting or retired, to go before a court since the 1980-1981 treason trial of Mao Zedong's wife and other members of the "Gang of Four" who persecuted political opponents during the 1966-76 Cultural Revolution.

Many other purged officials have been pushed out without trial, sometimes with fatal consequences.

___

LIU SHAOQI __ Once considered the anointed successor to communist leader Mao Zedong, Liu Shaoqi was swept from power at the beginning of the Cultural Revolution. Formerly upheld as the model of a proper communist, Liu was vilified as a traitor and the party's chief enemy, leading to his death in detention in 1969 following years of physical mistreatment, medical neglect and constant interrogation. He was later formally vindicated.

LIN BIAO __ Another putative heir-apparent to Mao, former star general Lin Biao died in a plane crash following his last-minute flight from China in 1971 after allegedly plotting a coup against the party leadership. Lin emerged after Liu's downfall, but fell out of favor amid the constant infighting and swirling intrigues of the Cultural Revolution.

JIANG QING __ Mao's third wife and leader of the radical Gang of Four that guided the Cultural Revolution, Jiang Qing was arrested after attempting to seize power in the inner-party struggle that followed Mao's death in 1976. Jiang was accused of persecuting political enemies and causing the suffering of millions, but claimed at her 1980 trial that she had only been doing Mao's bidding. Sentenced to life in prison, she committed suicide while on medical release in 1991.

HU YAOBANG __ Hu was credited with overseeing market-oriented economic reforms as party leader in the 1980s, but was also attacked by opponents for being too liberal and inspiring calls for greater political openness. Demoted in 1987, his death two years later provided the initial spark for the student-led pro-democracy protests crushed in Tiananmen Square on June 4, 1989.

ZHAO ZIYANG __ After succeeding Hu as party general secretary, Zhao Ziyang continued to advance popular economic reforms along with greater political transparency. After opposing the use of force against the 1989 student protests, Zhao disappeared from view and remained under house arrest in Beijing until his death in 2005. Despite his political exile and loss of freedom, Zhao was never charged with a crime or expelled from the party.

BO XILAI __ The son of a powerful Communist Party elder, Bo Xilai rose swiftly through the party ranks, despite making numerous enemies among the top leadership. His ultimate downfall came in 2012 in the midst of a scandal over his wife's alleged murder of a British business associate. Bo was subsequently ejected from the party and put on trial for corruption, although he vigorously denied the charges in a trial that was broadcast on television and publicized in court documents in a rare show of judicial openness.