Complex sentence: Negotiations between the two powers took place, but such was the distrust that in 506 the Romans, suspecting treachery, seized the Persian officials; once released, the Persians preferred to stay in Nisibis.
Split into simpler sentences: Negotiations between the two powers took place, but such was their distrust that in 506 the Romans, suspecting treachery, seized the Persian officials. Once released, the Persians preferred to stay in Nisibis.