Mączyński, along with ppłk Michał Karaszewicz-Tokarzewski won the battle for Lwów, which lasted for three weeks, and has taken the lives of 439 Polish and 250 Ukrainian soldiers. They took over the city on the night of 21/22 November 1918.&lt;ref name="publio.pl/files"&gt;&lt;/ref&gt; On the morning of 22 November Mączyński issued a proclamation to all inhabitants of Lwów regardless of creed or religion assuring that they have nothing to fear and their rights will be respected by the new Polish administration providing they don't take up arms. However, at about 9am that same morning a pogrom erupted in the Jewish Quarter. Within hours Mączyński was visited by the President of the Jewish Religious Community Emil Parnas with Emil Wasser requesting protection; also addressed by them, were Ernest Adam from "Polski Komitet Obywatelski" and President Władysław Stesłowicz. General Roja issued an order convening of courts martial in deserving cases, but Mączyński did not receive it until two days later, which was blamed on the office-shop mishap.