Training is how your economy becomes an army. You order a city to build a unit, pay for it, and it joins the map ready to move and fight.
What a unit costs
Every unit costs two things: currency from your treasury, and a permanent slice of the city’s population to crew it. Heavier units cost more on both counts, and a city can never spend its last resident, so training always leaves a city running.
How it works
The new unit appears near the training city, on the right footing for its domain. Land units need open ground nearby; naval units need reachable water, so a fleet has to be built from a coastal city.
How you interact with it
Because crew comes straight out of your population, every army is a trade against your economy. Raising a big force shrinks the workforce that feeds and funds you, so the question is rarely can you train, but what mix is worth the people, and when.
Why it matters
Training is the valve between economy and war. It converts the food, currency, and people you have grown into the combined-arms force you take to a fight, and how you spend that valve decides whether you can defend, push, or both.
This article reflects the game in active development and will change as systems evolve.