The document summarizes the development of long-distance trade networks like the Silk Roads from ancient times to around 400 CE. It discusses how empires and improvements in infrastructure supported expansion of trade routes. Goods like spices, grains, and silk were traded over land and sea routes between China, India, Persia, the Mediterranean, and East Africa. Major religions like Buddhism, Christianity, and Manichaeism also spread along these trade networks. However, epidemic diseases, political instability, and invasions contributed to the decline of the Han and Western Roman Empires by the 4th-5th centuries CE.