Complex sentence: The soldiers of the right wing followed them into the camp, at which many of the Persian army fled from the camp, except the ethnic Persian troops, who grouped together and fought the Greek soldiers who entered the camp.
Split into simpler sentences: The soldiers of the right wing followed them into the camp, at which many of the Persian army fled from the camp, except the ethnic Persian troops. These Persians grouped together and fought the Greek soldiers who entered the camp.