 Division of labor has been a feature from the beginning of civilization, the extent to which the division is carried out varied considerably depending on period and location.Compared to the Middle Ages, the Renaissance and the Age of Discovery were characterized by a greater specialization in labor, which was a characteristic of the growing cities and trade networks of Europe.An important leap in manufacturing efficiency came in the late eighteenth century as Eli Whitney popularized the concept of interchangeability of parts when he manufactured 10,000 muskets.