I've gotten way ahead of the competition on the technology curve, and discovered that I don't have any access to aluminum. So I allied myself with a city-state that has aluminum ... but they aren't building a mine to access it.

The same city-state has oil, and an extra work boat, but won't build an off-shore oil platform. (I've discovered the required tech for that as well.)

When and how do city-states discover resources? Do they do their own independent scientific research? Discover tech automatically in specific years? When some number or percentage of players have the technology?

Also, is it possible to help an allied city-state develop a resource they haven't discovered, by sending a worker to mine it for them, or a work boat to build an oil platform?

  • Is it too impractical (politically or socially) to just conquer the place? That seems like the easier solution to the problem.
    – Paul Z
    Commented Mar 19, 2012 at 20:18
  • They're pretty far away, so it'd take a while to get a melee unit there. Also, It'd be OOC, since I'm playing the good guy whose military might the villains of this world would do well to fear. Commented Mar 19, 2012 at 21:29
  • Have you tried sending a worker over there to build the mine? Commented Mar 22, 2012 at 13:47
  • You cannot use your own worker to work the tile of a City State or other nation's territory for that matter. Also, the question is not about if the player should conquer a CS for they resource.
    – Valamas
    Commented Mar 22, 2012 at 21:48
  • One of the gifts that you can give a cs is to develop a tile for them.
    – harmanjd
    Commented Oct 30, 2018 at 16:51

2 Answers 2


I am waiting for someone else to provide a better more accurate answer.

My observations are that City States can discover a resource before you do. An example of this is a city state I am allied with, will provide me with coal. However, I have not discovered coal and it does not even appear as a counter at the top of the screen yet. This proves that a city states technology is not in line with your own. A guess is they they would have access to all technologies cumulative of all player discoveries. This is because I find my greatest AI threat will upgrade to Infantry and then suddenly the city states around me upgrade to infantry.

Wildly guessing now! Another theory is that any CS that ally with a player gets their technology. If this is true, then it could mean that CS that are neglected as allies could have poor defence force technology. I will keep an eye on this on future games.

Secondly, if the city state does not have a worker they will be very slow to improve the tile. This is usually after they have survived a barb attack or foreign attack but have lost their only worker in the process.

I am unsure with the timeline of patches if city states do end up replacing workers because previously this was a problem. Not helped by a block that prevents gifting of workers. So no, you cannot help a CS with their tile improvements by using your own workers or by gifting workers.

As for the oil rig. It could be that they have discovered oil, but not oil rig tech. I am unsure about the build rate of worker boats. I do notice that the CS often works the sea resources quickly. But it could be a worker boat bug. i find that my automated worker boats will often move to a sea resource and then just sit on top of it. annoying. If the city state does the same, it could be connected to the same issue.

  • I wonder if it has anything to do with the type of city state that they are? I imagine that a Culturally focused city state would have less need for coal (or aluminum) than a Militaristic city state.
    – Albort
    Commented Mar 22, 2012 at 23:16
  • Thanks for sharing your observations. I'm pretty sure it isn't as simple as "the top tech that any player has discovered" (I'm not sure what you mean by "all"), since in my game, city states are still using riflemen, while Rome and I are using Mechanized Infantry and Paratroopers (respectively...I'm teching to Giant Death Robot, which means late mech. infantry). As far as the worker boats goes, city states with oil resources have had an extra workboat since the ancient era, it appears to be a tell. Commented Mar 22, 2012 at 23:19
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    @Albort That's an interesting observation...I've now gotten the aluminum I wanted from the two city states that had it this game, and the militaristic city-state gave me aluminum long before the cultural one. Perhaps there are three different timelines for the different city-state types, or if they do their own research, their different priorities affect which techs they choose to discover first. Commented Mar 22, 2012 at 23:30
  • Often I have noticed that when I am behind on tech that I also notice my AI enemy upgrade to infantry and city states around me upgrade to infantry. So when i say that I think City states have the technology of all. I am guessing/theorizing that they have access to all technology cumulative of all player discoveries to date in the game.
    – Valamas
    Commented Mar 22, 2012 at 23:35

City-states have access to any techs researched by at least one major civilization. Unfortunately you can't help or force a CS to develop its resources. In this case you can wait, trade with a major civilization, conquer the CS, or build a different selection of units.

  • 1
    Do you have a source for this? Because your answer is no different than the other, and I'm fairly sure it's not correct based on observed city-state behavior. Commented Apr 1, 2012 at 13:37

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