Mixed brigade

A mixed brigade (brigada mixta) was a tactical military formation of the Spanish Republican Army following the coup of July 1936 and the onset of the Spanish Civil War. It was the basic military unit of the Republican People's Army after its war-dictated 1936 reorganization.

The initial structure of this kind of brigade, approved in October 1936, was composed of four infantry battalions of five companies each, a mixed sapper battalion and a Service Corps company that included a medical corps group. Certain brigades had also a cavalry section. A division was composed of two or three mixed brigades.

The mixed brigade was based on a model that would replace the columns (columnas) and militias of the pre-coup Spanish Republican Army. The first six Mixed Brigades were created on 18 October 1936. The first was led by Communist colonel Enrique Líster, the second by Jesús Martínez de Aragón, the third by José María Galán, the fourth by Eutiquiano Arellano, the fifth by Fernando Sabio and the sixth by Miguel Gallo Martínez. By December 1936 there were fifteen brigades in full service (1st, 2nd, 4th, 5th, 6th, 11th and 12th International Brigades, 35th, 37th, 39th, 40th, 41st, 43rd, 44th, 50th and one unumbered). By the spring of 1937 there were 40 active brigades, and another 15 there were training. This brigades were swiftly placed in divisions.

Mixed brigades were typically Army units, however, the 151 Brigada Mixta, was a mixed brigade composed of Spanish Republican Navy Marines (Infantería de Marina) led by Commander Pedro Muñoz Caro. Photographer Robert Capa took pictures of the 151 Brigada Mixta in the Battle of the Segre.