1. From Adam Davidson in the NYT magazine:

At the city gate, Assur-idi ran into a younger acquaintance, Sharrum-Adad, who said he was heading on the same journey. He offered to take the older man’s donkeys with him and ship the profits back. The two struck a hurried agreement and wrote it up, though they forgot to record some details. Later, Sharrum-­Adad claimed he never knew how many textiles he had been given.

Pointer from Tyler Cowen.

This apparently took place in the 19th century, BC. Long-time readers will know that I have taken the view that archaelogists are finding evidence of plunder and calling it evidence of trade. But this example (read the whole story) shows that I am wrong about that.

The main focus of the article is the gravity model of trade, which says that trade between any two entities (cities, countries) is positively related to their size in terms of population and negatively related to the distance between them.

2. Josiah Ober says,

The key to unlocking the puzzling success of the Greek city-state ecology is economic specialization and exchange. Specialization was based on developing and exploiting a local advantage, relative to other producers, in the production of some valued good or service. . .

the costs of transactions were driven down by continuous institutional innovations, notably by the development and rapid spread of silver coinage as a reliable exchange medium; the dissemination of common standards for weights and measures; the creation of market regulations and officials to enforce them; and increasingly sophisticated systems of law and legal mechanisms for dispute resolution.

The whole piece is interesting.