There are also a few other effects that can directly change a pop's social class:

This ratio and the rate of change can be affected by player choices, and promotion is additionally restricted by the pop's level of civic rights based on its culture. The class structure of a territory's population will approach its optimal ratio over time through pop promotion and demotion, the value of which is specific to each territory and varies by the territory's buildings and rank, the country's government form, local and national modifiers, and many other factors. Slaves – generate tax income and additional trade goods.Tribesmen – generate manpower and tax income.Freemen – generate manpower and tax income.Citizens – generate research points, trade routes and manpower.Nobles - generate research points and trade routes.The social class of a pop is one of its most important properties and determines what a pop produces, its political weight, what happiness modifiers it is affected by, and more. A pop belongs to one of the five available social classes, or pop types.

Cities skylines mods origin