You know how your science advisor proudly tells you that "We have entered a new era!" but then nothing actually changes? Well, there are some cosmetic differences, like your city graphics change and your leaderhead gets a haircut, but nothing about the game changes at all! I believe each age should carry a distinct method of gameplay and city support. Here's a basic framework that doesn't touch on everything I'm thinking, but it's a start: Ancient - each city is basically on it's own. The city is the center of a 'hinterland' - the area of land necessary to support the city. Your borders should be determined by the placement of your citizens - if nobody's working those hills, you don't own 'em! And citizens can only be placed adjacent to existing citizens (including the city) There is no central economy - upkeep of each city must be paid for by each city. Science research is also per city (multiple cities can work on the same thing to pool resources, though). Units are free, but limited to 1 or 2 (or whatever) per city population (except artillery). Military control of unincorporated areas is the only method of control the wilderness. It now becomes relevant to besiege cities and wait them out. Forts and outposts are also more important and the 'landgrab' phase is eliminated - wilderness still exists after 600 BC! Corruption is determined by rank and distance. Medieval - Cultural borders are now defined by terrain improvements (whether they are worked or not), taxes are now pooled nationally, citizens can work any square within a certain radius of the city- much like current system of civ. Disputes over territory (improved but unworked squares) are determined by culture and military presence. Military presence can override culture on unworked tiles (tile belongs to the last person to invade it). Units are supported by the city from which they are produced (civ 2 style of upkeep). Corruption is still by rank and distance. Industrial - Nations exist with fixed borders based on cultural influence of cities. Any military within the borders constitues an invasion. Citizens can work any tile connected to a road or railroad regardless of distance from the city. Terrain can be specialized for different production, or "urbanized" for more population and trade. Army support is nationalized. Corruption by distance is diminished with the development of mass communications and railroad. Modern - Citizens no longer work tiles for a particular city. Food and sheild production are pooled into national "banks" and redistributed. Citizens instead are assigned to different industries which are affected by different city improvements. Diplomatic options, war, space race, etc... become the focus of the game and most micromanagement is eliminated. Corruption by distance is eliminated and is instead determined by city size, attitude, industries of citizens. More terrain specialization and urbanization lend character to cities and define regions. I basically want to represent the difference in the roles and shapes of cities in the history of civilization, while attempting to eliminate the boredom in the middle of the game. Thoughts?