Original sentence: After the Red Army liberated Lviv in the Lvov-Sandomierz Offensive of 1944, Banach returned to the University and helped re-establish it after the war years.His funeral at the Lychakiv Cemetery turned into a patriotic demonstration by the Poles.In January 1945, however, he was diagnosed with lung cancer
Edited sentence: After the Red Army restored the Soviet control over Lviv in the Lvov-Sandomierz Offensive of 1944, Banach returned to the University and helped re-establish it after the war years.His funeral at the Lychakiv Cemetery turned into a patriotic demonstration by the Poles who still remained in the city.However, because  the Soviets were removing Poles from annexed formerly-Polish territories, Banach began preparing to leave the city and settle in Kraków, where he had been promised a chair at the Jagiellonian University.In January 1945, however, he was diagnosed with lung cancer and was allowed to stay in Lviv