 Polesie Voivodeship was the largest province of interwar Poland.It ceased to function in September 1939, following the Nazi-German and Soviet invasion of Poland in accordance with a secret protocol of the Nazi–Soviet Pact of aggression.The provincial capital of the Polesie Voivodeship, and also the largest city was Brześć nad Bugiem (Brest-on-the-Bug) with some 48,000 inhabitants (1931).