The Gulag was the government agency that administered the main Soviet forced labor camp systems during the Stalin era, from the 1930s until the 1950s. The first such camps were created in 1918 and the term is widely used to describe any forced labor camp in the USSR. While the camps housed a wide range of convicts, from petty criminals to political prisoners, large numbers were convicted by simplified procedures, such as NKVD troikas and other instruments of extrajudicial punishment (the NKVD was the Soviet secret police). The Gulag is recognized as a major instrument of political repression in the Soviet Union, based on Article 58 (RSFSR Penal Code). The term is also sometimes used to describe the camps themselves, particularly in the West.