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.
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
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 or a province 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.
Each Citizen Pop at 100% Happiness produces per month:
- 0.25 Research Point
- 0.01 Commerce Value
- Base Happiness: 20%
Each Freeman Pop at 100% Happiness produces per month:
- 10 Manpower
- Base Happiness: 25%
Each Tribesmen Pop at 100% Happiness produces per month:
- 0.015 Base Tax
- 5 Manpower
- Base Happiness: 100%
Each Slave Pop at 100% Happiness produces per month:
- 0.035 Base Tax
- Base Happiness: 100%
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.
Happiness of pops
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.
- City's civilization value
- Trade goods
- Religion and culture different to the state's; assimilation and/or conversion
Population culture and religion
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.
Population of each social class can change through several means: Growth/Death and Conquest.
The base rate of population growth in each city in the game is 0.04%/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, Stability, and availability of trade goods. Note that all bonuses are additive, therefore population growth omen power may multiple the growth rate in every city you have.
- Omen: Blessing of Love: National Population Growth: +0.1% + omen power modifiers
- Being in peace gives 0.04%/month.
- Above 50 stability gives progressively more growth rate. Having 100 stability gives 0.5%/month, while having 50 stability or lower gives 0%/month.
- Livestock presence in the province gives 0.1%/month, while every additional one gives 0.05%/month in the province's capital city.
- Fish presence in the province gives 0.1%/month, while every additional one gives 0.05%/month in the province's capital city.
- Several laws give various, but very low rate of growth, typically between 0.01%/month and 0.05%/month.
- As of Pompey patch, grain presence no longer boosts pop growth, but improves the population capacity.
Aiming to boost your population size, you can aim first for the omen power, stability (while it gives the highest potential growth rate, it is the most costly to keep high), and the two trade goods presence in the province. Having multiple of the trade goods, or other modifiers have an extremely low benefit, but might be worthwhile.
When a new pop starts to grow, its social class is determined by chance, from the available pops already living in the city. Its culture and religion is also determined upon it starting to grow. They are also randomly selected from the religion and culture already present in the city. For example, if there is no Tribesman in the city, it will never start to grow. Though, it is possible to promote all of your (for example) tribesman into freeman, and still end up with one, if it was already growing when you have promoted the already grown ones.
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.
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.
Population moves between cities under 4 circumstances:
- Conquest (enslavement)
- Scripted Events
- The player can move slaves for gold
A slave 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 5 gold.
- Main article: Colonization
Populace is used to colonize new cities.
Slaves cannot be used when colonizing.