Civilize? These buildings represent the kind of government you install, particularly how you integrate the province into your empire. Have you read the descriptions?

For most factions, type I represent the core provinces. This is were most of the political power lies. Because of this, they are home to the political, economical and military elite. Obviously, only the provinces most closely aligned to your faction (i.e. those who share the same culture and ethnicity) can be turned into a type I province. Type II provinces are also aligned with your faction, but less important, usually because they are not as powerful or the inhabitants have other loyalties. Type III and IV government represent leaving the local political elite in charge, but with varying degrees of imperial interference.