In Empires, you represent a colonial European nation that is competing to gain the most support. Support is won by supplying your people with goods; goods are produced when your people work in your territories. You can gain people, territories, goods, and supporters by winning wars. To win wars, you must pay gold to raise armies, and gold can be earned by winning wars and by selling goods.
All turns are taken simultaneously, and there are no restrictions on trading. At any point in the game, you may trade anything: people, territories, goods, gold, player powers, etc. The game takes place over a series of rounds. At the end of the final round, the player with the most support wins.