Currency is the empire’s general-purpose resource. Unlike the physical resources, it is a single empire-wide treasury: it is not tied to any one city, and you spend it from one pool.
Earning it
Currency comes in steadily from your cities, from the land you have claimed, and above all from commercial buildings like shops and markets. Those only pay out while connected by road, so income districts live and die by their layout.
Spending it
Currency is the resource you reach for constantly. Founding and developing cities, claiming tiles, laying roads, constructing buildings, and training units all draw on the same treasury.
Why it matters
Because almost every action draws on the same pool, currency sets the tempo of your game. Commercial districts buy you the founding, claiming, and training that turn a foothold into an empire, so income is rarely something you can ignore for long.
This article reflects the game in active development and will change as systems evolve.