The Pavluk Uprising of 1637 was a Cossack uprising in Left-bank Ukraine and Zaporizhia headed by Pavlo Mikhnovych against the Polish-Lithuanian Commonwealth. The rebellion was sparked by several Cossacks expelled from the Cossack Registry. Mikhnovych ordered the captured commanders of the Registered Cossacks to be executed and issued a declaration, in which he proclaimed a fight against the masters. Defeated by the forces of Mikołaj Potocki in the Battle of Kumejki in 1637, he was brought to Warsaw, tried and executed. The uprising was bloodily quelled, only to restart the following year in the form of the Ostrzanin Uprising, also defeated by the Commonwealth.