Diplomacy
Discovering new factions
You can discover new locations by clicking on question marks on the world map [M]. You can send out expeditions starting form you community centre which requires workforce and bread to explore new locations.
It is possible that certain areas are too far away. In this case, you need to discover other locations first.
You can make agreements with other discovered factions in the diplomacy view next to the map. It is possible that certain diplomacy options require certain rights to unlock other rights.
Trade Agreement
Sets up an agreement to trade with each other, which allows so buy and sell goods over the market place.
Way Of Right
Allows you to travel through their territories to reach distant places. This may unlock new locations.
Free Trade
Sets up an agreement to not collect duties or fees. Without this option, the buyer has to pay additional 8% of the item value to the seller.
Settling Rights
Allows you to settle on their land. This unlocks the option to send material and people to this region.
Collaboration
Sets up an agreement to help each other out. This is usually required to ask them to join you.
Join
Asks if they want to join your faction. All their people and buildings will be transferred to your faction. Be aware that this includes their market place.