After Axis attack on Soviet Union 1941, Poland was occupies by Germany.
Polish citizens suffered enormous human and material losses.
According to institute of National Remembrance estimates about 5,6 million Polish citizens died as a result of German occupation 150,000 died as result of the Soviet occupation.
Polish Jews (close to three million people) were murdered as part of Holocaust, killed as masse at Nazi extermination and camps, such as Auschwitz, Treblinka and Sobibor.
Germans had future plans to turn the remaining majority of Poles into slaves
September 1939:
Polish government officias sought refuge in Romania. General Wladislaw Sikorski arrived in France where a replacement Polish government was formed.
After tall of France government evacuated to Britain.
Resistance movement began in Poland in 1939 soon after invasions. Largest military component was part of Polish Underground State.
Than Sikorski agreed to form a Polish army in Soviet Union.
Further the Polish Soviet cooperation failed because of disagreement over the borders, discovery Katyn massacre, and death of General Sikorski.
A new Polish army formed in Soviet Union to fight together with Soviets.
Polish communists founded the State National Council in 14943/44 in occupied Warsaw in July 1944 in Lublin after arrival the Soviet Union army.