Complex sentence: He was quickly outflanked by the Roman advance; just as the spartans had been by the Persians 300 years earlier.thus resulting in the Roman victories at Thermopylae (191 BC) and the Battle of Magnesia (190 BC).
Split into simpler sentences: He was quickly outflanked by the Roman advance; just as the spartans had been by the Persians 300 years earlier. Thus, resulting in the Roman victories at Thermopylae (191 BC) and the Battle of Magnesia (190 BC).