Each of you pays me one gold. And next turn I'll have an army at Istanbul capable of closing the straits to trade. In future turns, as they make money, players will try to escape their obligations by use of their own empire's forces and thus realize greater profits for their personal duchies. At the same time, their empires will probably acquire independent lands giving them a greater stranglehold on trade and more profits. An important point is that imperial treasuries may not be shared with personal treasuries, although players will find ways of using the empire to enhance their own profits.
Turns are seasonal.
Navies move during Spring and Summer turns while armies and caravans operate during Summer and Fall. Nothing moves during the Winter. But during each season, a card is turned up and placed up for auction to all duchies. Cards represent princesses, spies, pirates, assassins, painters, engineers, reformation leaders, heretics, explorers, and most importantly, new ventures, including voyages of exploration. Handled abstractly, players may discover India and the New World which provide new sources of silk, spice and gold.