Rise of Cultures revolves around improving your relations with allied cultures while expanding your own. There are many cultures to discover throughout the game, but these groups can be divided into Home Cultures and Allied Cultures.
Home Cultures consist of the ages and eras you progress through within your home city, and each has a correlating research tree that improves along with your age. New home cultures provide new designs and levels to your home city buildings, new goods to unlock, and new questlines to follow.
Allied Cultures act as friendly cities which you control, and provide a new family of goods, quests, and resources.