Flechas Negras Mixed Brigade

In 1937, during the Spanish Civil War, Italians from the Corpo Truppe Volontarie began to serve in mixed Italo-Spanish Flechas (Arrows) units where the Italians provided the officers and technical personnel, while the Spanish served in the rank-and-file. One, the Flechas Negras Mixed Brigade "Black Arrows" first served in Vizcaya from April 1937.

Order of Battle, April 1937
Flechas Negras Brigade - Col. Sandro Piazzoni
 * 3rd Regiment
 * 1st Battalion
 * 2nd Battalion
 * 3rd Battalion
 * Battery 65/17
 * 4th Regiment
 * 1st Battalion
 * 2nd Battalion
 * 3rd Battalion
 * Battery 65/17
 * Assault Battalion
 * 1st Company
 * 2nd Company
 * Artillery Group
 * IVº Grupo de 75/27
 * Grupo de 100/17
 * Grupo de 105/28
 * Battery 20mm AA
 * Engineer Company
 * Intendencia Section
 * Sanitation Section

Order of Battle, Battle of Santander August 1937
Flechas Negras Brigade - Col. Sandro Piazzoni
 * 3rd Regiment
 * 1st Battalion "Monte Jata"
 * 2nd Battalion "Bermeo"
 * 3rd Battalion "Munguia"
 * Battery 65/17
 * Engineer Section
 * 4th Regiment
 * 1st Battalion "Peña Amarilla"
 * 2nd Battalion
 * 3rd Battalion "Algorta"
 * Battery 65/17
 * Engineer Section
 * Assault Battalion
 * Artillery Group
 * Group 75/27
 * Battery 149/12
 * Antitank Battery 37mm
 * Battery 20mm AA
 * Engineer Company
 * Division Truck Unit

The Flechas Negras Brigade was later expanded to form the Flechas Division.