The Italian Communist Party (Italian: Partito Comunista Italiano, PCI) was a communist political party in Italy. The PCI was founded as Communist Party of Italy on 21 January 1921 in Livorno, by seceding from the Italian Socialist Party (PSI). Amadeo Bordiga and Antonio Gramsci led the split. Outlawed during the Fascist regime, the party played a major part in the Italian resistance movement. It changed its name in 1943 to PCI and became the second largest political party of Italy after World War II, attracting the support of about a third of the voters during the 1970s. At the time it was the largest communist party in the West (2.3 million members in 1947 and 34.4% of the vote in 1976).