He was a Voivode of Nowogródek Voivodeship from 1931 to 1932, and of Polesie Voivodeship from 1932 to 1939.
•
Under pressure from Russian diplomats the authorities of Austria-Hungary refused and Kostek-Biernacki had to flee to France, where he joined the French Foreign Legion.
•
Following the Oath Crisis of 1917 and Legions' switching sides, Biernacki was interned in Beniaminów together with a large group of former soldiers of the Legions.
Remnants crossed the Vistula on September 10 and joined the Northern Front of General Stefan Dąb-Biernacki, fighting in the Battle of Tomaszów Lubelski.
She participated in the Scandinavian Congress of Mathematicians, International Colloquium on the Theory of Functions, in Helsinki the very same year in August and had the opportunity to meet some of the famous Mathematicians like Ernst Hölder, Wilhelm Blaschke, Lars Valerian Ahlfors, Paul Montel, O. Lehto, M. Biernacki, Alexander Gelfond, A. Pfluger, W. Kaplan, Walter Hayman and Paul Erdős.