The earliest form of retail merchandising was probably the exchange of food and weapons; later came traders and peddlers, and by 3000 BC shops had become common. During the Greek and Roman period, stores, including many specialty shops, developed in the form of open booths, attracting large cosmopolitan crowds. After the decline of the Roman Empire, barter became more important, but by the 14th cent. retail trade again assumed importance. Merchants, who in early times were viewed with suspicion, rose in the social scale. Small stores, each carrying its special line of goods, reached their peak in the 18th cent. The wholesale business developed, and traveling salesmen and standard prices came into general use.
In the United States the general store preceded the single-line store and is still common in small rural communities. In the late 19th cent. the department store came into being—a large-scale general store or a combination of single-line stores in which each line of merchandise is operated as a separate department. Such stores provide the convenience of easy accessibility to a large variety of goods. Modern department stores have been vital to the development of shopping centers and malls, huge retail developments that contain a wide variety of stores and services.