Instead of corporations, how about adding philosophies? In the ancient world, Greek philosophies had a huge impact on the post-Hellenistic Mediterranean world. Doing a wikipedia search for philosophy (Hellenistic philosophy to be exact) yields nine major philosophies, with two of those (Hellenistic Judaism and Neoplatonism) being concerned with religion. Leaving off the latter two philosophies leaves seven, a magic number (it seems) for Civ IV. Even if the philosophies don't use the corporation mechanic, they can just use a modified version of the religion mechanic. (I can't think of resources that would get sacrificed to grant bonuses for most philosophies. Maybe Epicureans and Hedonists would both lose the use of certain luxuries in their cities-- the former because they abstained from using those resources, and the latter because they consumed them all!) Each philosophy could give different bonuses, based on their focus. For instance, military units built in Stoic cities might get +1 (or possibly +2) experience, based on the principles of acting in correct judgment in response to suffering. Stoic cities might also suffer an additional +1 if running slavery, and/or slave quarters may generate an additional Skeptics could generate more , either per city or as part of their special building, Eclectic cities could generate more , etc. I personally think having a bonus and a penalty for each philosophy would be the best way to run it, especially if the benefit slightly outweighed the penalty. I just can't think of specific examples for all seven philosophies right now.