Quite simple: a region is the geographical zone where people lived and/or particular events took place. A period is the chronological segment of linear history (timeline) where such people lived and/or the event took place. For example, the Crusades took place in the Middle East while the period is the Middle Ages.
Answer: They traded and learned from each other. The Rome's allies helped it conquer other lands but were tricked because they were being conquered themselves.
