Ryszard Kaczorowski was born on 26 November 1919, in a wooden house at 7 Mazowiecka Street in Piaski District of Białystok. The house stood at the intersection of Mazowiecka Street with the no longer existing Argentyńska Street., Białystok, Poland. His parents were Wacław Kaczorowski, of Jelita and Jadwiga (née Sawicka). In 1920, when Białystok was overrun by Soviet forces during the Polish-Soviet War, it briefly served as headquarters of the Polish Revolutionary Committee headed by Julian Marchlewski, which attempted to declare the Polish Soviet Socialist Republic. The city again changed hands after the Battle of Białystok, when the city was liberated by the 1st Legions Infantry Division and 5th Legions' Infantry Regiment. The family witnessed certain dramatic results of the battle from a small wooden house typical at Argentyńska Street.