What discovery has made the persian gulf a center of population and trade?

The discovery that has made in the Persian Gulf that made it as a center of population and trade is oil. It is because through the discovery of oil, it had led to the rise of its economy, making a change in its economy and made it considered that the countries of the Persian gulf to have a significant percentage of the world’s oil reserves and production.

the roman army grew in size and became dominant in the mediterranean region.