There have been occasional periods of intense economic integration over the centuries, most notably during the Roman Empire and in the latter half of the 19th century. These have shared several common features: for example, technological innovations that shrank economic distances (e.g., standardized roads, the telegraph and, more recently, the Internet) and, very importantly, governments that pursued supportive economic policies.
These governments recognized the long-term benefits of economic integration and were large enough to internalize the costs – both political and fiscal – of promoting public goods such as the rule of law; common standards for trade, products, and services; and the liberalization of trade.