The Biennio Rosso (English: "Red Biennium" or "Two Red Years") was a two-year period, between 1919 and 1920, of intense social conflict in Italy, following the First World War. The revolutionary period was followed by the violent reaction of the fascist blackshirts militia and eventually by the March on Rome of Benito Mussolini in 1922. The Biennio Rosso took place in a context of economic crisis at the end of the war, with high unemployment and political instability. It was characterized by strikes and mass worker demonstrations, as well as self-management experiments through land and factory occupations. Tension had been rising since the final years of the war, and some contemporary observers considered Italy to be on the brink of a revolution by the end of 1918. The population was confronted with rising inflation and a significant increase in the price of basic goods, in a period when extensive unemployment was aggravated by mass demobilization of the Royal Italian Army at the end of the war. Association to the trade unions, the Italian Socialist Party (PSI), and the anarchist movement increased substantially. The PSI increased its membership to 250,000, the major socialist trade union, the General Confederation of Labour (Confederazione Generale del Lavoro, CGL), reached two million members, while the anarchist Italian Syndicalist Union (Unione Sindacale Italiana, USI) reached between 300,000 and 500,000 affiliates. The anarchist movement was boosted by the return from exile of its prominent propagandist Errico Malatesta in December 1919. In Turin and Milan, factory councils – which the leading Italian Marxist theoretician Antonio Gramsci considered to be the Italian equivalent of Russia's soviets – were formed and many factory occupations took place under the leadership of revolutionary socialists and anarcho-syndicalists. The agitations also extended to the agricultural areas of the Padan plain and were accompanied by peasant strikes, rural unrests, and armed conflicts between left-wing and right-wing militias.