features a mix-and-match system that lets you choose which civilization you want to play as during the three distinct Ages. Not all of these civilizations will be available after selecting an initial civilization during game setup, though.
Depending on which Civ a player chooses for the Civ 7 Antiquity Age, options for the Exploration and Modern Ages are limited to some extent; only a few become automatically available based on the geographic or historical thread that ties them to the player's initial choice (i.e.
the Han, Ming, and Qing path). However, you can actually select any Civ you want in the later Ages by completing specific tasks or challenges during gameplay.
You can view the various Unlock conditions during gameplay on the Player Unlocks screen, which provides a full breakdown of each civilization's unlock requirements.
These range from constructing different types of buildings or improvements to having a set number of Army commanders in a given Age.