The population of the world is represented by individual "population units", or 「pop」 for short. Each population unit has a unique ID in the save game file.
Pops are the basic generator of 
Money (commerce + Taxes), 
Manpower and 
Research Points.
Social classes
A pop belongs to one of the four available social classes. It is the social class which determines what a pop produces!
- Citizens – generate research points and commerce income
- Freemen – generate manpower
- Tribesmen – generate manpower and tax income
- Slaves – generate tax income; additionally produce surplus goods
- Promotion of 1 pop costs 10
Oratory Power Points, regardless whether Slaves ⇒ Freemen, Tribesmen ⇒ Freemen or Freemen ⇒ Citizens.
Population cannot be demoted by the player! But
- when a city is being sacked, there is a chance that Citizens will be demoted ⇒ Freemen and Freemen ⇒ Slaves. Some Slaves are "teleported" to the state's capital at no cost, no matter how far away.
- switching the Governor Policy of a province to "Social Mobility", will lead, in due time, to a 33%, 33%, 33% distribution. Tribesmen remain unaffected.
公民
Each Citizen Pop at 100% Happiness produces per day:
- 0.25 Research Point
- 0.01 Commerce Value
- Base Happiness: 20%
自由民
Each Freeman Pop at 100% Happiness produces produces per day:
- 10 Manpower
- Base Happiness: 25%
部落民
Each Tribesmen Pop at 100% Happiness produces per day:
- 0.015 Base Tax
- 5 Manpower
- Base Happiness: 100%
奴隸
Each Slave Pop at 100% Happiness produces per day:
- 0.03 Base Tax
- Base Happiness: 100%
Additionally for every 15 slave pops in a city one additional trade good is produced. terrain type "Farmlands" requires 2 less.
Productivity
As already explained, pops are the only generator of Money, Research and Manpower! And there is a great many modifiers. For the human player to keep a better overview, there is the productivity-modifier, similar to 
Discipline for armies. It affects whatever the pop produces and is itself affected by various parameters throughout the game. Some of the modifiers to productivity are:
- #Happiness of pops
- Civilization level
E.g. the Centralization affects the productivity of 
Tribesmen.
Each pop has its own culture, religion and social class. The happiness value is applied to all pops sharing the same of the former three features living in a city.
人口的幸福度
Happiness impacts two things on the pop:
- #productivity: e.g. a freemen-type pop at 50% happiness generates only 5 Manpower instead of 10. at 150% happiness it generates 15 manpower!
- unrest: any pop with happiness less than 50% generates unrest to the city it currently resides in. A city with high enough unrest triggers a rebellion.
Each of the four #Social classes comes with its base happiness of 20%, 25%, 100% and 100%. Then the game defines a great deal of modifiers:
- city's civilization value
- Ideas
- Inventions
- Laws
- Trade goods
- religion and culture different to the state's; assimilation and/or conversion.
Aggressive expansion points additionally affect pops with divergent culture and religion.
人口文化和宗教
As each state has its own State Culture and Religion, so does each pop unit have its own as well. When a pop's religion and/or culture differs from the state in which it resides that pop's happiness is affected. Each individual pop's culture and religion can be separately converted to match the state's own for a price.
- Assimilation of 1 pop costs 20 Oratory Power Points
- Conversion of 1 pop costs 20
Religious Power Points
獲得人口
Population of each social class can change through several means: Growth/Death and Conquest.
Growth/Death
The base rate of population growth in each city in the game is 0.2/day (or month?). When this number reaches 100% a new pop of that type is born in that city. There are many modifiers to this value. The population growth in a city is altered by factors such as terrain type, Civilization value, amount of pops currently living in the city (-1% per pop) and availability of trade goods.
- Omen: Blessing of Love: National Population Growth: +0.1%
- When a new pop is born, its social class is determined by chance. (25% each)
Population growth in a city can also become negative (by modifiers). If this happens the growing pop will shrink instead. If there is no growing pop an existing pop will be chosen (at random) and a progress bar toward 0 will start. If it reaches 0% that pop will die.
Conquest
Population is also gained through warfare. As cities are sacked, POWs are taken to the state capital or to the provincial capitals as slaves. It should be noted, that pops within the newly conquered city may be demoted:
- Citizen ⇒ Freemen (50% chance)
- Freemen ⇒ Slaves (50% chance)
Tribesmen and Slaves never change their social class upon conquest.
Pop Movement
Population moves between cities under 3 circumstances:
- Conquest (enslavement)
- Scripted Events
- Player interaction for
Civic Power Points
A pop can be moved from a city to any city in the same province, an adjacent city or a city across an adjacent sea-zone for a power cost of 20 Civic Power.
Slaves are cheaper than other pops to move, and only cost 5 Civic Power to transfer. Since the number of slaves in a city influences the production of Trade Good, this means that you can more easily set up production centers for certain goods.
殖民
- 主條目：Colonization
Populace is used to colonize new cities.
Slaves cannot be used when colonizing.
參考資料