Within this context socialism has undergone four periods: the first in the 19th century was a period of utopian visions (1780s–1850s); then occurred the rise of revolutionary socialist and Communist movements in the 19th century as the primary opposition to the rise of corporations and industrialization (1830–1916); the polarisation of socialism around the question of the Soviet Union, and adoption of socialist or social democratic policies in response (1916–1989); and the response of socialism in the neo-liberal era (1990– ). As socialism developed, so did the socialist system of economics.