Amadeo Bordiga was an Italian revolutionary socialist and Marxist. He was most prominent in the 1920s, which is when he founded the Communist Party of Italy (PCdI). Over time he fell out of favor with the party as it embraced Bolshevization and he was finally expelled in March of 1930. Later in life he was a leading figure of the International Communist Party (ICP), for which he wrote his most popular works. His writings emphasize an "invariant" party program, proletarian internationalism, and anti-reformism. Bordiga is a central figure of the Communist Left.