Its members were from a number of different countries thus it was also known as "Forty Nations Brigade" (Spanish: Brigada de las cuarenta naciones).

Its first leader was Polish officer Wacław Komar, who had previously led the Dombrowski Battalion in the XIII International Brigade.

[2] The beginning of the rebel Aragon Offensive necessitated the swift transferring of the CXXIX International Brigade to the eastern part of the Iberian System.

[1] The other units of the division became isolated in Catalonia when the territory held by the Spanish Republic was split in two by the swift crumbling of the loyalist defense in Aragon.

In September the unit attained distinction in battle in combats and skirmishes around the Alto del Buitre and the Sierra de Javalambre, being collectively awarded the Medal of Bravery.

[4] In the middle of the Republican debacle in Catalonia the former CXXIX International Brigade members joined other foreign volunteers who had chosen to remain in Spain and tried to defend Vic.