Cities within a league can trade with each other. The labor used for transportation is provided by the exporting city. Trade, production, and consumption are organized by the player, subject to constraints described below. He instructs each city in his league how to allocate its annual labor among different goods and which of the goods it produces should be shipped to other cities. Goods cannot be stored, so consumption is production plus goods shipped from other cities minus goods shipped to other cities.
Trade occurs only within a league.
League Expansion and Contraction A league may at any time send trade missions to try to persuade non-member cities to join. Supporting a trade mission, like producing or transporting a good, costs a certain amount of labor. Missions to more distant cities cost more. A city bases its decision to join a league on its observation of the benefits that the league confers on its member cities. If the invitation is refused another mission can be sent the next year.