What were the Phoenicians were great?

Since the Phoenicians were an ancient shipbuilding, seafaring and trading civilization of the Middle East, one could say that the Mediterranean Sea was their greatest natural resource. In addition, since they invented the art of glass-blowing, the sands of Arabia could also be thought of as one of their greatest Natural Resources.

Alternative:

The could generate a surplus if cedar timber, purple dyes, pottery, metal ores.