Complex sentence: The huge Seleucid empire had the biggest manpower of all the other hellenic states however the seleucids didnt really train and enroll natives in the army and thus they were the auxillier troops.
Split into simpler sentences: The huge Seleucid empire had the biggest manpower of all the other hellenic states. However the Seleucids didnt really train and enroll natives in the army and they served as auxillier troops.