The Silk Roads were made up of an indirect chain of separate transactions through which goods crossed the entire land area of Eurasia. Rarely did merchants themselves travel the length of these routes; in fact, few of them knew the complexity and breadth of the Silk Roads. Merchants primarily engaged in local instances of "relay trade" in which goods changed "hands many times before reaching their final destinations."[1] Because the Silk Roads crossed land it was much more expensive and dangerous to move goods. Consequently, trade focused on luxury items that would bring a nice profit making the greater risks worthwhile. Particularly important were luxury items with a high value to weight ratio.
In the classical era and before, trade mainly existed within the empires. Greek, Roman, Persian, and Indian states grew agricultural produce and created other material goods that were traded throughout the city states and regions of the empire.
