The Gulag was the government agency in charge of the Soviet network of forced labour camps which were set up by order of Vladimir Lenin, reaching its peak during Joseph Stalin's rule from the 1930s to the early 1950s. English-language speakers also use the word gulag in reference to each of the forced-labor camps that existed in the Soviet Union, including the camps that existed in the post-Lenin era. The full official name of the agency changed several times.
The Gulag is recognized as a major instrument of political repression in the Soviet Union. The camps housed a wide range of convicts, from petty criminals to political prisoners, a large number of whom were convicted by simplified procedures, such as NKVD troikas or other instruments of extrajudicial punishment. In 1918–1922, the agency was administered by the Cheka, followed by the GPU (1922–1923), the OGPU (1923–1934), later known as the NKVD (1934–1946), and the Ministry of Internal