Complex sentence: He gained military experience in the fight against the rebellious Cossacks during the Severyn Nalyvaiko uprising under Field Crown Hetman Stanisław Żółkiewski, in which he participated in the Battle of Kaniów on April 14,1596, and in the siege of the Cossack tabor near Lubny.
Split into simpler sentences: He gained military experience in the fight against the rebellious Cossacks during the Severyn Nalyvaiko uprising under Field Crown Hetman Stanisław Żółkiewski. During that conflict he participated in the Battle of Kaniów on April 14,1596, and in the siege of the Cossack tabor near Lubny.