Each campaign begins following the selection of a faction. Each one has a unique start position and different strategic advantages. Factions are split into two types: major and minor factions. A major faction is playable based on their geographical position and importance during the period covered by the grand campaign. A minor faction is unplayable, but will still make conquests. Each faction belongs to a culture that dictates its style of buildings and types of unit.
Every faction belongs to a culture that dictates its style of buildings and the types of unit available to it. There are five culture types: Roman, Hellenic, Punic, Barbarian, and Eastern. Dignitary agents can be sent ahead of an army to spread your culture amongst a population before you conquer them, heading off any public order problems that may arise if you conquer a region belonging to a different culture.
Each faction has a set of characteristics particular to them, known as faction traits. These work in a similar way to character traits but are present from the start of a campaign, rather than awarded as it progresses. Each trait has one or more effects that bestow a bonus or penalty on an aspect of the faction's activities, check the summary tab on the faction panel to see them. Faction traits are always permanent.