In history, religion, and political science, a purge is the removal of people who are considered undesirable by those in power from a government, another organization, their team owners, or from society as a whole. A group undertaking such an effort is labeled as purging itself. Purges can be either nonviolent or violent; with former often resolved by simple removal from office, and latter with the imprisonment, exile, or murder of those purged.
The earliest use of the term itself was the English Civil War's Pride's Purge. In 1648-1650, the moderate members of the English Long Parliament were purged by the army. Parliament would suffer subsequent purges under the Commonwealth including the purge of the entire House of Lords. Counter-revolutionaries such as royalists were purged as well as more radical revolutionaries such as the Levellers. After the Restoration, obstinate republicans were purged while some fled to New England.
The Shanghai massacre of 1927 and the Night of the Long Knives of 1934, in which the leader of a political party turned against and killed a particular section or group within the party, are commonly called "purges" while mass expulsions on grounds of racism and xenophobia, such as the Crimean Tatars and the Japanese-American internment are not.
The term "purge" is often associated with the Stalinist and Maoist regimes. While leading the USSR, Joseph Stalin imprisoned in Gulag-labor camps and executed, i.e. purged, "wreckers", or citizens accused of plotting against communism. Stalin initiated the most notorious of the CPSU purges, the Great Purge, during the 1930s.