This country (the Roman Empire) has more than four hundred smaller cities and towns. It extends several thousand li in all directions. The king has his capital (that is, the city of Rome) close to the mouth of a river (the Tiber). The outer walls of the city are made of stone. - A Third Century Chinese Account Composed between 239 and 265 CE, Quoted in zhuan 30 of the Sanguozhi. Published in 429 CE. Draft English translation
Networks of the Hanseatic League - The Hanseatic League was a late-medieval network of economically largely independent long-distance trade merchants which was based on trust, reputation and reciprocal relations. The informal cooperation among its members kept transactional, informational and organizational costs low, allowing the Hanse merchants to make good profits from the long-distance trade between the Baltic and the North Seas. Thanks to personal and institutional links with confederations of towns, the Hanse merchants were initially able to strengthen their international position of power. Since the late 15th century, however, the transaction costs of long-distance trade increased as a result of growing exclusivity and formalization efforts in the Hanseatic league. Moreover, changes in the European economic structure, triggered by the discovery of America, and internal conflicts ultimately led to the disintegration of the Hanseatic networks.
The Seljuk Han in Anatolia has tons of information about and pictures of the caravanserai, inns for caravans, built by the Seljuk Sultanate of Rûm in what is now Turkey. The Seljuk caravanserai, called hans, were a vital resource for trade from the middle ages to recent times. The website, by Katherine Branning, explains what a han is, their origins, their function in trade, what life there was like and much more. The site also features 39 individual hans, such as the Kadin Han, now a furniture store, Dibi Delik Han, which is undergoing restoration, Zazadin Han, which has been restored already, and the spectacular Sultan Han Kayseri. For an academic survey of Seljuk hans, here's Ayşıl Tükel Yavuz' The concepts that shape Anatolian Seljuq caravanserais [pdf, automatic download].