Original: Events By place Roman Empire Roman Emperor Trajan completes his invasion of Parthia by capturing the cities of Seleucia , Babylon , Ctesiphon and Susa , marking the high-water mark of the Roman Empire 's eastern expansion .
Simplified: Events Roman Emperor Trajan completes his invasion of Parthia by capturing the cities of Seleucia , Babylon , Ctesiphon and Susa , marking the high-water mark of the Roman Empire 's eastern expansion .