At the beginning of the war Soviet troops occupied Lvov. Banach had been on good terms with the Soviet mathematicians before the war started, visiting Moscow several times, and he was treated well by the new Soviet administration.
Sa simula ng digmaan Sobiyet tropa abala Lvov. Banach had been sa magandang terms sa Sobiyet mathematicians bago ang digmaan na nagsimula, pagbisita sa Moscow ng ilang beses, at siya ay tratuhin nang maayos sa pamamagitan ng mga bagong Sobiyet pangangasiwa.