How to change the initial map of a faction?

Hello, friends! I would like to know how to change the initial map of a faction. For example, in the original rome the greeks don't begin having Corinto, since this city belongs to Macedonian.

Another question: how can I create a new city for a faction?


As always, thank you for the answer

Look at the map tutorials on the Campaigns & Maps section of the Scriptorium.

Thank you, friend!