But as I noted above, what happens in Civ3 is already a fairly abstract representation of human history. And as players/ modders, we are limited in how we can represent these abstractions, such as the development of new techs, or the adoption of new governments, by the hardcoded tech-, government-, and building-flags available in the Editor(s). So the development and application of "early agriculture" is arguably already modelled by Irrigation — but the potential outputs are limited by the intial government being Despotic (hence the "mine green, irrigate brown [+ Food-bonuses on flatland]" rule of thumb for the early game). One of the highest priorities in the early game is then to learn and adopt a new government which does not penalise tile-yields. Arguably this represents the more complex forms of society you describe above. (noting that Code of Laws is already required for Republic — and should arguably also be required for Monarchy!) And this at least may already be moddable to a lesser or greater extent. If @Flintlock (or @Quintillus?) could decouple the "Increases food from [salt]water tiles" building-flag from the saltwater tiles, and allow it to be applied to all (irrigated?) land-tiles as well — using the same code that currently only applies to Rails? — then a generic "Watermill" building could be added which could increase a town's food-yield, and hence growth rate and/or productivity (weren't watermills also used to power some medieval/early industrial processes?). Any mod with such a building would probably also need additional constraints to prevent the surfeit of food from becoming completely unbalancing, though: — To prevent Watermills from being built everywhere, they might also be given the flag(s) "Must be near a river" (would anyway be logical!) and/or "Requires [Wheat] in the town radius"; the latter has the drawback(?) of also requiring [Wheat] to be set as a Strategic/ Luxury resource, which will change its distribution-pattern on a random map — Citizens might reuire 3 food per turn to prevent starvation, instead of only 2 FPT — Some/all post-Ancient military units might also need to consume a population-point(s), in addition to their shield-costs Or the Watermill could work similar to the "Granary", "Maize farm" and "Dairy Farm" SWs in @haluu's Tides of Crimson, autoproducing a unit whose only purpose is to be joined to a town, to increase its population. Improving food-yields in the early medieval might be accomplished by allowing a new building with say, Engineering or Feudalism. But we do already have the generic Granary, which 'improves' food-yields by halving the amount of food required for growth — so it might just be simpler (even if historically less 'accurate'! ) to move the Granary to a later point in the tech-tree. Alternatively, add locational-constraints to the "Ancient" Granary, as described above for the hypothetical Watermill — but also allow a "Medieval" Granary to be built which has no such limitations. In the patch's .ini file, yes. But at the moment the patch only allows to set a single, hardcoded limit. Are you asking whether the patch could be used to impose multiple potential movement-limits, which were e.g. tech-dependent? That would be really cool, especially if it could also be applied to Roads. Then you wouldn't need any extra Worker-jobs, because "Build Road" could then cover both a rutted track (increased commerce but no movement-bonus?) to a paved road (movement-factor per the .biq; unlocked with... Construction?) — and "Build Rails" could cover both steam-powered (rail-movement limited per the patch, as at present), and modern diesel/electric locomotives / superhighways (unlimited movement*; unlocked with... Motor Transport? Computers? Ecology?) * Spoiler Digression : I have never had a conceptual problem with unlimited rail-movement in the epic-game. On a global map, with turn-lengths of a year (or more) of in-game time, it makes gameplay 'sense' to me, for my units to be deployable anywhere around my continent within a single turn. Conversely, the horribly 'slow' naval movement-rates, even into the Modern Age, have always been far more immersion-breaking from my PoV. That said, I can certainly see a good case for Rail-movement to be limited in mods/scenarios with prebuilt small-scale regional/urban maps, and/or turn-lengths on a much shorter scale of e.g. hours to days (e.g. EFZI, SuperCiv).