Diplomacy, when and why?

[MarcelB]

Unfortunately, the tutorials do not guide you to the meanings and functions of the diplomacy menu. Could someone explain to me please, what I do with this menu and in which cases I need it and in which way it is best to handle...? I hope I made myself clear enough. Thanks in advance.

[Dobber]

It is used to interact with the other players in the game, asking for trade agreements, peace treaties, alliances, war declarations and such.
Just click on the portrait of the player you want to interact with and then choose the appropriate buttons for the actions you wish to carry out!