Complex sentence: When two of his brothers, Tzanis Mavromichalis and Petros were treacherously captured by government forces under Ioannis Capodistrias, Konstantinos and the old bey's son Gorgeos Mavromichalis decided to take revenge.
Split into simpler sentences: When two of his brothers, Tzanis Mavromichalis and Petros were treacherously captured by government forces under Ioannis Capodistrias. Kostantinos and the old bey's son Gorgeos Mavromichalis decided to take revenge.