When, at the outbreak of World War II, the Germans invaded Poland, the Molotov–Ribbentrop Pact then divided the country, allowing German control of the west, and Soviet control of the east. In June 1941 the Germans launched Operation Barbarossa, capturing eastern Poland, which was occupied until 20 July 1944, when the 1st Byelorussian front, under the command of Marshal Konstantin Rokossovsky, crossed the Bug River in three places and began an advance on Lublin and Brest, in the direction of Warsaw. Major battles took place at Radzymin and Wolomin, with heavy losses on both sides. On 2 August the Soviets redirected their assault from Warsaw northwards to Wyszków and the River Liwiec, a switch thought by some to evidence Stalin’s reluctance to aid the Polish nationalists’ uprising in Warsaw (1 August–2 October).
— OR —