Complex sentence: The Spartans recalled him once again, and Pausanias returned because he didn't wish to be suspected of Persian sympathies, on his arrival in Sparta the ephors had him imprisoned but he was later released.
Split into simpler sentences: The Spartans recalled him once again, and Pausanias returned because he didn't wish to be suspected of Persian sympathies. On his arrival in Sparta, the ephors had him imprisoned but he was later released.