Jan Krupa walczyl w II Wojnie Swiatowej, z Niemcami w czasie okupacjii Polski.

Polish resistance movement in World War II

The Polish resistance movement in World War II, with the Polish Home Army at its forefront, was the largest underground resistance movement in all of occupied Europe,covering both German and Soviet zones of occupation. The Polish resistance is most notable for disrupting German supply lines to the Eastern Front, providing military intelligence to the British, and for saving more Jewish lives in the Holocaust than any other Western Allied organization or government. It was a part of the Polish Underground State. Wikipedia