Andreu Nin (1892-1937) was the leader of the pro-Trotskyist POUM (Unified Marxist Workers Party) which was founded after a merger of Izquierda Communista and Bloc Obrer Camperol (worker and Peasant Bloc), led by Joaquin Maurin. He also acted as Trotsky's personal secretary for a certain time (Note that Trotsky himself had critised the POUM). At the outbreak of the Spanish Civil War, Nin was killed by Stalinist agents.