The XII International Brigade was mustered on 7 November 1936 at Albacete

Albacete

Albacete is a city and municipality in southeastern Spain, 258 km southeast of Madrid, the capital of the province of Albacete in the autonomous community of Castile-La Mancha. The municipality had a population of c. 169,700 in 2009....

, Spain. It was formally named the Garibaldi Brigade, after the most famous and inspiring leader in the Italian Independence Wars, General Giuseppe Garibaldi

Giuseppe Garibaldi

Giuseppe Garibaldi was an Italian military and political figure. In his twenties, he joined the Carbonari Italian patriot revolutionaries, and fled Italy after a failed insurrection. Garibaldi took part in the War of the Farrapos and the Uruguayan Civil War leading the Italian Legion, and...

. Its first commanding officer was a soviet advisor of Hungarian origin, Gen. "Pavol Lukács" (Máté Zalka), who went on to command the 45th Division of the Spanish Republican Army (he was killed during the Huesca Offensive).

The brigade included, among others, the following battalions:

• Garibaldi Battalion
  Garibaldi Battalion
  The Garibaldi Battalion was a group of mostly Italian volunteers that fought in the Spanish Civil War from October 1936 to 1938...
  
   - Albanian
  Albanians
  Albanians are a nation and ethnic group native to Albania and neighbouring countries. They speak the Albanian language. More than half of all Albanians live in Albania and Kosovo...
  
  , Italian and Spanish volunteers
• André Marty Battalion - Franco-Belgian volunteers (named after André Marty
  André Marty
  André Marty was a leading figure in the French Communist Party, the PCF, for nearly thirty years. He was also a member of the National Assembly, with some interruptions, from 1924 to 1955; Secretary of Comintern from 1935 to 1944; and Political Commissar of the International Brigades during the...
  
  )
• Dabrowski Battalion
  Dabrowski Battalion
  The Dabrowski Battalion, also known as Dąbrowszczacy was a battalion of the International Brigades in the Spanish Civil War. It was initially formed entirely of volunteers, "chiefly composed of Polish miners recently living and working in France and Belgium". Because of the relatively short...
  
   also known as the Dombrowski Battalion - exiled Polish volunteers
• Thaelmann Battalion - German and Austrian volunteers (named after Ernst Thälmann
  Ernst Thälmann
  Ernst Thälmann was the leader of the Communist Party of Germany during much of the Weimar Republic. He was arrested by the Gestapo in 1933 and held in solitary confinement for eleven years, before being shot in Buchenwald on Adolf Hitler's orders in 1944...
  
  )
• Figlio Battalion - Spanish volunteers
• Madrid Battalion - Spanish volunteers
• Prieto Battalion - volunteers