Petro Kalnyshevsky was a prominent Ukrainian military leader who served as the last Kish otaman of the Zaporozhian Sich between 1765 and 1775. Born in 1691 in the Romny Raion area, he rose through the ranks, serving as an osavul in 1754 before reaching the highest office. His leadership was marked by significant changes to the Cossack administration and the expansion of grain production. Following the liquidation of the Sich by Catherine the Great, he was arrested and sent into exile on the Solovetsky Islands, where he lived until his death in 1803.