
Originally Posted by
KrashKrunal
Firstly converted cities may have Library's or Marketplaces, and/or their upgrades, which'll be why they seem faster, however if you build the same in your own city, it will produce the same.
Also note that the Mongols get +50% trade in captured cities, so that may be another reason.
And finally... it's down to teh population. The higher the population, the more production you get.
Oh and anything that's good for research will be good for gold, just build a Marketplace/Bank instead of a Librart/University.