Third International in the context of "Second International"

The history of socialism has its origins in the Age of Enlightenment and the 1789 French Revolution, along with the changes that brought, although it has precedents in earlier movements and ideas. The Communist Manifesto was written by Karl Marx and Friedrich Engels in 1847-1848 just before the Revolutions of 1848 swept Europe, expressing what they termed scientific socialism. In the last third of the 19th century parties dedicated to democratic socialism arose in Europe, drawing mainly from Marxism. The Australian Labor Party was the first elected socialist party when it formed government in the Colony of Queensland for a week in 1899.

In the first half of the 20th century, the Soviet Union and the communist parties of the Third International around the world, came to represent socialism in terms of the Soviet model of economic development and the creation of centrally planned economies directed by a state that owns all the means of production, although other trends condemned what they saw as the lack of democracy. The establishment of the People's Republic of China in 1949, saw socialism introduced. China experienced land redistribution and the Anti-Rightist Movement, followed by the disastrous Great Leap Forward. In the UK, Herbert Morrison said that "socialism is what the Labour government does" whereas Aneurin Bevan argued socialism requires that the "main streams of economic activity are brought under public direction", with an economic plan and workers' democracy. Some argued that capitalism had been abolished. Socialist governments established the mixed economy with partial nationalisations and social welfare.

World communism, also known as global communism or international communism, is a form of communism placing emphasis on an international scope rather than being individual communist states. The long-term goal of world communism is an unlimited worldwide communist society that is classless, moneyless, stateless, and nonviolent, which may be achieved through an intermediate-term goal of either a voluntary association of sovereign states as a global alliance, or a world government as a single worldwide state.

A series of internationals have proposed world communism as a primary goal, including the First International, the Second International, the Third International (the Communist International or Comintern), the Fourth International, the Revolutionary Internationalist Movement, Maoist Internationalist Movement, the World Socialist Movement, and variant offshoots. The methods and political theories of each International remain distinct in their pursuit of the global communist society.

The Unified Socialist Party of Catalonia (Catalan: Partit Socialista Unificat de Catalunya, PSUC) was a communist political party active in Catalonia between 1936 and 1997. It was the Catalan branch of the Communist Party of Spain and the only party not from a sovereign state to be a full member of the Third International.