Complex sentence: He served a teaching post as a history teacher at Athens College, in Greece and posts at Wabash College and Hamilton College and was principal of Phillips Exeter Academy between 1974 and 1987.
Split into simpler sentences: He served a teaching post as a history teacher at Athens College, in Greece and posts at Wabash College and Hamilton College. He was principal of Phillips Exeter Academy between 1974 and 1987.