In June 1831, after the death of Field Marshal von Diebitsch, commander of Russian troops in Congress Poland, Paskevich was appointed his successor in crushing the Polish uprising. His armies, following the decisive success of Diebitsch at the Battle of Ostrołęka in May, advanced slowly, but Paskevich redeemed his reputation at the Battle of Warsaw, giving a death blow to Polish hopes of restoring independence. He was created "Prince of Warsaw" and awarded the office of Namestnik of the Kingdom of Poland. With the kingdom's autonomy limited by the Organic Statute of the Kingdom of Poland, the period under Namestnik Paskevich – known in Poland as the "Paskevich Night" – became infamous for political and economic repressions, as well as for Russification.