In World War II , the members of this family suffered many military and ethnic-based casualties in the following incidents ; the Polish Defensive War September – October 1939 , Katyn massacre and the related Smolensk region massacres , Nazi concentration camps , Nazi crimes against ethnic Poles , Soviet Gulags and military deaths in resistance movements or as anti-Axis members of the British , Soviet or French armies . This led to a collapse of the kinship by 20 – 50 % in several branches of the family while some became extinct altogether . Furthermore , the loss of the heart of the Jankowski h. Jastrzebiec lands in the Polish Eastern borderlands ( Kresy ) , to the Soviet Union , led to a large proportion of the surviving Jankowski descendants relocating west into new Poland . However , a second wave of political emigration overseas also followed . This time , a sizable proportion went to the UK and its commonwealth , as many Poles including the Jankowski diaspora had fought with distinction in the II Corps ( Poland ) of the British Army and the Polish Air Force as part of the Royal Air Force during the war
Katyn massacre
Katyn massacre
Jankowski