Complex sentence: Unfortunately for the success of the invasion, Aristagoras quarrelled with the Persian admiral Megabates when he interfered in the discipline of the latter over the ship captains to save a friend from harsh punishment for an infraction.
Split into simpler sentences: Unfortunately for the success of the invasion, Aristagoras quarrelled with the Persian admiral Megabates. He interfered in the discipline of the latter over the ship captains to save a friend from harsh punishment for an infraction.