The unit was created in May 1937 from elements of the 2nd Division of the People's Army of Catalonia, under the command of the Lieutenant Colonel of the Civil Guard Mauricio García Ezcurra. The brigade was assigned to the 33rd Division,[1] initially heading to the Andalusian front and later, to the front of Guadalajara, where it spent the rest of the conflict.
Between 5 and 7 April 1938 it took part in the fighting that took place in the so-called "Vertice Cerro", in the province of Cuenca, facing fourteen enemy assaults against its positions that left the brigade seriously damaged. A few months later, in August, the 138th Mixed Brigade took part in various actions that took place in the Universal Mountains.[2]
During the rest of the war it did not participate in relevant military operations.
Alpert, Michael (1989). El ejército republicano en la guerra civil (in Spanish). Siglo XXI Editores.
Álvarez, Santiago (1989). Los comisarios políticos en el Ejército Popular de la República (in Spanish). Ediciós do Castro.
Engel, Carlos (1999). Historia de las Brigadas Mixtas del Ejército Popular de la República (in Spanish). Madrid: Almena. ISBN84-922644-7-0.
González Huix, Francisco J. (1995). El puerto y la mar de Tarragona durante la Guerra Civil, 1936-1939 (in Spanish). Institut d'Estudis Tarraconenses «Ramon Berenguer IV».