Konashevych-Sahaidachnyi, Petro

(1582–1622) was a Cossack hetman, who transformed the Cossack Host from an erratic military formation into a regular army. The Cossacks, the Orthodox clergy and peasants emerged as a united nation under his leadership. His troops played a significant role in the battle of Khotyn against the Turks in 1621, and in Prince Władysław’s attempt to gain the Moscovy throne in 1618