Note: This procedure involves editing a game file create a backup copy of the file before proceeding. You can also use this method to unlock some of the non-playable factions, though some of those to play may be bugged. It can also be unlocked by a modding of the game's files. More Factions can be unlocked for use in Campaign by successfully obtaining victory before rival factions in either the Normal Campaign (Become Supreme Ruler of Rome and hold at least 50 provinces), or the Short Campaign (Destroy or Outlast certain factions, hold at least 15 provinces) Unlocking more factions for use in campaign When you first begin a Campaign, the Julli's first mission from the Senate will be to capture a nearby village Settlement.
The three religious temples for The House of Julli are Ceres, wp:Dionysus Bacchus, and Jupiter. They also have a unique unit to their faction(and the Senate and People of Rome), Samnite Gladiators, which are effective swordsmen with excellent morale and can be built once a Colosseum (Entertainment Building) is created. They start with two settlements in the northern part of the Italian Peninsula, with Arretium as their capital. The House of Julli are the red colored Roman Faction. All Senate missions will add popularity gained to the Senate in your Senate Floor. Some of the missions have rewards for completing them such as money or unique Military units to be used in battle, or are required by the Senate or else they will put punishments upon you. The Senators will assign missions to the three Roman starter Factions(including the player if he is playing as Julli, Scipii, or Brutti) in which they will have to complete a military task such as capturing an enemy settlement, blockading an enemy port with one of your fleets a diplomatic task, such as getting trade rights, map information, or creating an alliance with another faction or it could involve personal tasks, such as killing your own faction leader(Usually only happens when you get high influence over the Plebeians(People of Rome)which is required to overthrow the Senate and take over all other Roman factions and establish your own empire). They have only one city, Rome(which is the most advanced city when you start a Campaign).
The Senate and People of Rome are the big boss of the three starting Roman factions in the Campaign(The House of Julli, The House of Scipii, and The House of Brutti, each representing the historical Julian, Scipio, and Brutus families, respectively).
Brigands are revolting slaves, Pirates are Rebel Fleets, The Gladitor Uprisings come from Roman Cities with the Arena type of buildings, Amazons from the Northern Steppe areas near Scythia, Helot Rebels from Sparta(which have a large morale boost to their army), or just independent kingdoms and city-states. There are different kinds of Rebels as well. For example, a Rebel army near Rome could have lighter more militia-like soldiers such as Town Watch, while a Rebel army near Athens could have Hoplites and Peltasts and other Greek Soldiers. The units of the Rebels depend on the culture of the faction they came from. Just like their name, they usually come about by unhappy people who go against their nation.