How to Join an Alliance
To join an Alliance you need 1 unused Diplomacy Point. When you build a level 1 Embassy (see picture) you get 3 Diplomacy Points, whic can also be use to make a Military Treaty or a Trade Treaty with other players. you dont "spend" those points, you just allocate them fo the time beeing. You can always break the treaty a any point an get back you diplomacy point. If you need more Diplomacy Points, you would have to upgrade your Embassy.
Before you can unlock the Embassy, you have to research Foreign Cultures which is under Navigation, and to get to research that, you need to meet all the dependencies:
- Conservation -> Pulley -> Wealth (Economy)
- Dry-Dock (Military), required for Deck Weapons
- Well Digging -> Paper -> Espionage (Science)
- Deck Weapons -> Ship Maintenance -> Expansion -> Foreign Cultures
You may find this Ikariam Tech Tree useful.
Ikariam Tips:
Upgrade your Embassy only if you know what you want it for.
The Military Treaties are have been know to be bugged since the beginning of the game: it doesn't work.
If you want to found your own Alliance, try to get some support first. Specially support from people close to you, and see if people are willing to donate you large quantities of marble.