Ancient civilizations traded a wide array of commodities, including livestock, seashells, spices and gold. Although the quality of product, date of delivery and transportation methods were often unreliable, commodity trading was an essential business. The might of empires can be viewed as somewhat proportionate to their ability to create and manage complex trading systems and facilitate commodity trades, as these served as the wheels of commerce, economic development and taxation for the kingdom's treasuries. Reputation and reliability were critical underpinnings to secure the trust of ancient investors, traders and suppliers.
( Extracts from: An Overview Of Commodities Trading| Investopedia http://www.investopedia.com/articles/optioninvestor/09/commodity-trading.asp#ixzz4IWRoSA8V )