Fidel Castro came to power through a coalition group known as the 26th of July Movement. Along with it, in 1959, the Student Revolutionary Directorate (Directorio Revolucionario Estudiantil) and the Communist Party (Partido Socialista Popular—PSP) were permitted to function.
Castro's relationship with the PSP was at first uneasy. The PSP condemned his early attempts at insurrection as "putschism," and did not support the 26th of July Movement until it had reached its final stages in 1958. After June 1959, Castro began to refer to anti-Communists as counterrevolutionaries, and used the PSP as an organizational base and as a link to the USSR. In December 1961, Castro declared his complete allegiance to Marxism-Leninism.
By 1962, the 26th of July Movement, the Student Revolutionary Directorate, and the PSP had merged into the Integrated Revolutionary Organization (Organización Revolucionaria Integrada), which, in turn, gave way to the United Party of the Socialist Revolution (Partido Unido de la Revolución Socialista) and, in 1965, to the Cuban Communist Party (Partido Comunista Cubano—PCC).
On 17 December 1975, the PCC convened its first congress, which ratified a 13-member Politburo; Fidel Castro was reelected first secretary of the PCC. The second congress of the PCC took place in December 1980. The third congress, in February and November-December 1986, witnessed a massive personnel change when one-third of the 225-member Central Committee and 10 of 24 Politburo members were replaced, with Fidel Castro reelected first secretary. The Young Communist League and the José Martí Pioneer Organization for children up to 15 years of age are mass political organizations closely affiliated with the PCC. As of 2003, the PCC remained Cuba's only authorized political party.