Complex sentence: With the destruction of the Zaporozhian Sich in 1775, only a few of the most senior Cossacks were repressed such as Holovaty's older brother Pavlo who was one of those arrested with the last Zaporozhian kosh otaman Petro Kalnyshevsky.
Split into simpler sentences: With the destruction of the Zaporozhian Sich in 1775, the most senior Cossacks were repressed. Among them was Holovaty's older brother Pavlo who was one of those arrested together with the last Zaporozhian kosh otaman Petro Kalnyshevsky.