A war fought between Finland and the Soviet Union. The Finnish government under General Mannerheim had rejected Soviet demands for bases and for frontier revisions similar to those accepted by the lesser Baltic states. Soviet armies attacked on three fronts, and at first the Finns’ superior skill in manoeuvring on skis on the frozen lakes and across the Gulf of Finland, and in the forests of their country, kept the Soviet forces at bay. After 15 weeks of fierce fighting the Soviets breached the Mannerheim Line and Finland was forced to accept peace on Stalin’s terms, ceding its eastern territories and the port of Viipuri (Viborg).