During the Second World War he was a member of the Polish resistance, leading the grouping Confederation of the Nation (merged into the Armia Krajowa in 1943) and taking part in the fighting around Vilnius.
This passage describes a person who was involved in the Polish resistance movement during World War II, specifically with the Confederation of the Nation, which later merged into the Armia Krajowa. He participated in combat operations near Vilnius.