Joaquín Maurín Juliá (Catalan: Joaquim Maurín, 12 January 1896 – 5 November 1973) was a Spanish communist politician and activist. The leader of the Workers and Peasants Bloc (BOC) and of the Workers' Party of Marxist Unification (POUM), he was active mainly in Catalonia. Early life Born in Bonansa in Huesca, Aragon, Maurín engaged in socialist politics from early youth and stood trial on several occasions. CNT and Profintern After law studies, he practiced in Lleida (Catalonia), where he became affiliated with the anarchist Confederación Nacional del Trabajo (CNT, "National Confederation of Labour"). In 1920, Joaquín Maurín was elected local secretary for the trade union, as well as the editor of its weekly Lucha Social. In 1921, he represented the movement at the Profintern Congress in Moscow, the capital of Soviet Russia. Upon his return, he was elected general secretary of the CNT shortly before was arrested and detained in February 1922. After his release, Maurín founded the Comités Sindicalistas Revolucionarios ("Revolutionary Trade Union Committees") as a Bolshevik group within the CNT. He also gave the committees their own press tribune, La Batalla, in December. Communist Party of Spain In 1924, he led his La Batalla into a merger with the Communist Party of Spain and took charge of organising the latter's local wing, the Catalan-Balearic Communist Federation (FCCB). During the crackdown on opposition parties that was ordered by the dictator Miguel Primo de Rivera, Maurín was arrested and jailed in January 1925. Released in 1927, he opted to leave Spain for Paris. However, he returned to Barcelona in 1930 and worked for the reanimation of La Batalla in the months before the proclamation of the Second Spanish Republic in early 1931. He became opposed to Stalinist policies in the Soviet Union and took a stand that saw him grouped with the emergent international Right Opposition. He split with the Communist Party of Spain and led the FCCB into independent politics. (His wing's place in the Stalinist body was quickly taken over by the Communist Party of Catalonia.) BOC and POUM On 1 March 1931, the FCCB joined with the Catalan Communist Party and, in 1933, became the Iberian Communist Federation and declared its goal to occupy a place on the national stage. The unified body of the FCCB and the Catalan Communist group became the mass front Workers and Peasants Bloc (BOC), with Maurín as its general secretary. The