ENIn August 1939 all main Polish military units from Grodno and Wilno garrisons were mobilized to fight against German army and were send to the west frontline. This way, both cities were left without regular army’s units, remained defenceless against Soviet aggression. It was impossible to stand up the fight in this situation. The only way for the reserve units, which have stayed, was evacuation from Poland to Lithuania. Many officers of Fortified Areas Grodno and Wilno had to make a difficult decision: to stay and fight or to leave Poland and go to Lithuania. This dilemma, one among many others, had influence on their attitudes and decisions during this tragic time.