Player Properties Dialog
Allows you to set the properties of the players in the scenario. For each player in your scenario, you can override global defaults for treasury, starting units, difficulty level, starting era, government, and free technologies, as well as color, name, and gender.

NOTE:
in order to enable this dialog, the "Custom Player Data" option in the Scenario menu must be enabled.

Click anywhere on the image for help on that part of the screen.