Krzysztof Kosiński

Krzysztof Kosiński, also Kryshtof Kosynsky of Rawicz Coat of Arms (Криштоф Косинський, Kryshtof Kosynsky; Krzysztof Kosiński; 1545–1593) was a Cossack noble from the Podlachia region. He was a colonel of the Registered Cossacks and self-proclaimed Hetman of Ukraine. He led two consecutive rebellions against local Ruthenian nobility, known as the Kosiński Uprising.

His forces were first defeated by Duke Janusz Ostrogski in the Battle of Piątek on 2 February 1593. Kosiński promised to subject his forces to the Polish Monarchy; however, he soon escaped to Zaporizhzhia, where he began organizing a new army. In 1593 he set out for Cherkasy but was soon killed.

Kosiński uprising (1591–1593) is a name applied to two rebellions in the eastern parts of the Polish–Lithuanian Commonwealth (modern-day Ukraine) organised by Krzysztof Kosiński against the local Ruthenian nobility and magnates.