If you have run into Iii in Civilization and moved on without quite understanding it, this is the explanation.

Short answer

It matters more than its screen time suggests, which is why it keeps coming up.

  • Ask what it is for before asking how to get it.
  • Do not confuse it with the similarly named thing — that mix-up drives most bad advice.
  • Write down what you changed, so you can undo exactly one thing if it goes sideways.

Each Civilization entry reshuffles the rules enough that habits from the last one quietly stop working. The wiki entry is thorough and buries the actually useful part six paragraphs down. It is more consequential in the late game than the early one, which is why first impressions mislead.

Why people keep asking about it

The awkward part is rarely the step itself, it is knowing which step comes first. Community shorthand around it has drifted far enough from the original meaning to cause arguments. It rewards understanding rather than grinding, which is unusual for Civilization. Treat anything stated without a version number as provisional.

The name is descriptive if you already know what it does, and opaque if you do not. If you only remember one thing about it, remember where it appears. If you are coming to this after a long break, the terminology has probably moved on.

How it has changed over time

It shows up in more places than its introduction suggests, once you know to look. There is a persistent myth attached to it that has never been true in any version. Patch notes move numbers around constantly; the shape of the answer holds even when a specific value shifts.

  • Check which version of Civilization any discussion of it is describing.
  • Ignore the myth attached to it; it has never held up.
  • Region and platform change more than people expect, so confirm both.
  • Note where it first appears, so you can go back if you need to.
  • It rewards attention rather than preparation.
  • Prefer the in-game option over an external tool when both exist.

What it is

It became noticeably more relevant after a change the patch notes barely mentioned. Its role has changed across updates, so older discussion describes something slightly different. Nothing here assumes a particular playstyle beyond wanting the thing to work. Whether it is worth going out of your way for depends entirely on how you are playing.

It appears in supplementary material in more detail than it does in the game itself. If a step reads as obvious, do it anyway — the obvious ones are the ones people skip and then wonder about. Most guides mention it in passing and none of them stop to define it.

How it connects to the rest of Civilization

Knowing this does not make you better at Civilization, but it does make the rest of it legible. None of this needs a paid tool, a third-party launcher or an account on a site you have never heard of. Its practical value is narrow and real, rather than broad and theoretical.

Two similarly named things exist, and mixing them up explains a lot of contradictory advice. A single check up front replaces a lot of guessing later. It is the kind of thing veterans forget they ever had to learn.

What it changes in practice

The in-game description is technically accurate and practically useless. The developers have changed their mind about this at least once, which explains the older advice. Early impressions of it are usually wrong in the same specific way.

Where people go wrong

  • Assuming a guide from an older season still describes the current version.
  • Rushing the last step, which is usually the one with the actual requirement in it.
  • Grinding a method that was patched months ago because a thread still ranks well.

Civ FAQ

Does this work the same on console and PC?

The logic is identical. Menu paths and button prompts differ, and any real difference is flagged above.

Can I miss it?

Where it is missable, that is noted above. Most players meet it without going looking for it.

Why do other guides describe this differently?

Most were written for an earlier version and never revisited. Compare the steps against what your build actually shows.

Do I need any mods or third-party tools for this?

No. Everything described here works with the base game on any supported platform.

If you only take one thing from this: the answer near the top is the part that matters, the rest is context.