M. I. Finley's "The Ancient Economy", which i just finished reading, was an eye opener. Evidently all "trade routes" and enterprises, in the ancient world, have to be thought of as passive receptions, the door is open, operations. Something of an idea of what he's presenting is represented by the thought that, though Gibbons has us spellbound with the thought that the entire army of Rome, at the hight of Rome's power and its widest extent, was not larger than Louis XIV's army Finley suggests that the Romans would never have been able to make that gesture, that might of conquest, which was so much a necessity in the reality of France in the 17th Century. Could not, because the idea of state wasn't as strong as the theology of superstition. People, ordinary parvenues, gave, donated, to the public coffers and graneries because they wanted to, they Had to as a part of their duty to the natural world.
Finley was a history professor at Cambridge, England. the book is the record of a public lecture series he gave in Berkeley, is user friendly.
here's a link to a better description of the book:
http://www.powells.com/biblio/0520219465
orren. g.