The International Brigades (IB) were volunteer military units of foreigners who fought on the side of the Second Spanish Republic during the Spanish Civil War. The number of combatant volunteers has been estimated at between 32,000–35,000, though with no more than about 20,000 active at any one time. A further 10,000 people probably participated in non-combatant roles and about 3,000–5,000 foreigners were members of CNT or POUM. They came from a claimed "53 nations" to fight against the Spanish Nationalist forces led by General Francisco Franco and assisted by German and Italian forces. The volunteers were motivated to fight on political or social grounds and made their way to Spain independently of the Spanish government. The brigades were not initially formally conceived and methodically recruited. Instead, they evolved as a means of organising the streams of volunteers arriving from every quarter of the world. It has been estimated that up to 25% of IB volunteers were Jewish. This article describes the order of battle of each of the International Brigades, describing the order and manner in which each brigade was mustered and formed, and following the progress of individual battalions throughout the conflict.

Introduction

Early International units

The first volunteers arrived in Spain in mid-August 1936. These were mostly Franco-Belgian, German, British and Italian. At first, they grouped themselves into sections, called Columns or Centuria (nominally of a hundred men). These were mostly formed in August/September 1936.

Brigade structure

Each brigade was a mixed brigade consisting of four battalions, sometimes with an ancillary specialist support company. They had a brigade commander and a political commissar, and a small brigade staff. Initially, the battalions were formed entirely of foreign volunteers but, increasingly, it became practice to have at least one Spanish battalion in each brigade (and, from spring 1937, one Spanish company in each battalion). As time went on, and the difficulties of recruiting new international volunteers increased, the percentage of Spaniards went up. At first, these were volunteers but conscription was later introduced. The brigades were formally incorporated into the Spanish Army in September 1937, as Spanish Foreign Legion units.

Battalion structure

The battalions were originally organised by language, with volunteers sharing the same (or similar languages) and given names that reflected the groups. To develop an esprit de corps, these names were replaced by names of inspirational figures or events, for example, Garibaldi, or Commune de Paris. "Theoretically, the Battalion organisation consisted of the Battalion Commander, his Second in Command, the Political Commissar, the Adjutant and orderly room staff, three Companies of infantry, one machine-gun Company, Battalion scouts, and the Quartermaster and cookhouse staff. There were three platoons in each company, each divided into [four] sections of ten men, so that the Battalion at full strength would number more than 500 men...."

Political commissars

See article: Political commissar

International brigade depots

XI International Brigade

Names: Songs by Ernst Busch and the choir of the XI Brigade: Detailed Order of Battle

Formation

Brigade staff

Division "Kléber" (XI and XII Brigade 20 Nov.36 - 4 Feb 37 )

XII International Brigade

Name: The Garibaldi Brigade Detailed Order of Battle

Formation

Raised 22 October 1936 at Albacete, General "Lukàcs" (Mate Zalka) commanding. (Lukàcs was killed during the Huesca Offensive.)

XIII International Brigade

Names: The Dabrowski Brigade, The Dombrowski Brigade Detailed Order of Battle

1st formation

Raised: 12 December 1936

2nd formation

Reformed: 4 August 1937

3rd formation

Reformed (in Monredón): 1 October 1938 (exclusively Spanish battalions)

4th formation

Reformed: 23 January 1939 (from demobilised International Brigade members who had remained in Spain)

Brigade staff

XIV International Brigade

Name: The Marseillaise Brigade Order of Battle

Formation

Raised 20 December 1936 with volunteers mainly from France and Belgium, under General "Walter" (Karol Świerczewski). After the Battle of Brunete (6–25 July 1937), brigade strength was reduced from four to two battalions. The battalions attached to this Brigade at different times were:

XV International Brigade

Order of Battle ! Date joined ! Number ! Battalion Name ! Composition ! Date left ! Comments

Other International Brigades

86th Brigade

Raised 13 February 1938

CXXIX / 129th Brigade

Name/s: Central European Brigade Raised 13 February 1938

CL / 150th Brigade

Name/s: Dabowski Brigade Raised 27 May 1937

Ad hoc units

Catalonia Offensive Catalonia Offensive