The Communist Party of Peru was created in 1928. Originally it was called the Socialist Party of Peru, but its name changed to the Communist Party of Peru (in Spanish, Partido Comunista Peruano) in 1930. The founder and ideological leader of the Communist Party of Peru (PCP) was José Carlos Mariátegui. In 1935 the PCP was accepted into the Comintern. The party was illegal, but in spite of severe underground conditions it conducted work. The PCP rallied workers, organized the anti-fascist movement, and in the late 1930s attempted to control the solidarity movement with republican Spain.
From 1940 to 1942 the PCP experienced a serious internal crisis, when the PCP's General Secretary Eudocio Ravines and a right wing faction of the party began steering the party into a Browderist national unity popular front. This faction was expelled from the party.
During World War II and afterward, with the working class becoming empowered along with the national liberation movement in the country, the changing conditions caused the party's influence to become stronger with the masses and the PCP became a legal party. At the PCP's third congress in 1948, a program was accepted. The PCP had 40,000 members at the time.
Nevertheless, the PCP played a role in the 1950 uprising in Arequipa and the mass strike movement from 1954 to 1955. In 1956 the party became legal again, which allowed the PCP to work more actively. In 1959, the PCP expanded solidarity work with the Cuban Revolution.
The PCP's fourth congress accepted resolutions which discussed the problem of developing a union of industrial workers and peasants as the basis of a democratic forces bloc in the country. In the beginning of 1963 PCP was again subjected to repression, about one thousand communists were arrested, including leaders such as Jorge del Prado, and Acosta.
The Sino-Soviet split and the questions it raised helped to split the PCP in January 1964 - the Moscow-leaning faction with del Prado and Acosta started a party which was nicknamed PCP "Unidad" after its newspaper, while the Peking-leaning faction containing Saturnino Paredes and José Sotomayor started a party that was nicknamed PCP "Bandera Roja" (PCP-BR) after their periodical.
In January 1968, a faction of PCP-BR left the party and started a party which was called CPP "Patria Roja".