Nomads established themselves in the oasis. The nomads desperately need wool and grain and offer commodities of the desert in exchange for them. Since the Cataners always have a few sheep and grain sheaves left over, the nomads send caravans out, in order to trade for the desired raw materials.
Through the course of the game, three caravan routes are formed with the caravan arrows. All settlements and cities on the caravan route count for one more victory point. Any road running alongside the caravan's route counts double for the trade route.