In late October 1936, the first shipments of Soviet military aid, including aircraft, tanks, and advisors, began arriving in Republican Spain, significantly bolstering the Republic's defense capabilities. The Soviet aid, which was coordinated through the Comintern, included T-26 tanks and I-15 and I-16 fighter planes that proved crucial in the defense of Madrid. The Soviet intervention, however, also increased the influence of the Spanish Communist Party and contributed to tensions with anarchist and socialist groups within the Republican coalition.

The Soviet aid inspired a wave of pro-Communist poetry among Republican writers, who praised the Soviet Union as the defender of the Republic. Poets like Rafael Alberti, who became increasingly aligned with the Communist Party, wrote verses celebrating the Soviet tanks and planes. The Soviet intervention also introduced a new vocabulary of revolutionary struggle into Spanish poetry, with words like 'tank' and 'airplane' becoming symbols of modern warfare.