Diplomatic status

In the [r]eports menu, you can access your [d]iplomacy report. This report shows you your status toward other countries, and their status toward you. You start out UNMET with all nations. Then, as your armies come close to their sectors, or vice-versa, the two nations will meet and be put in neutral status.

You can change your status to other countries. A lot of statuses are possible, but the most important ones are:
ALLIED gives permission to the other nation to pass through your land at a lower move cost. Also, you can put your armies in GARRISON in allied land, and they will get 1/2 of the GARRISON bonus.

TREATY goes beyond ALLIED: if your armies or those of the other nation are involved in a battle, and the other has armies on the same sector, the two will fight together. Also, if you put your armies in GARRISON in treaty land, they will get the full GARRISON bonus.

WAR If any army of yours is on the same sector as an enemy army, and one of the two is on ATTACK or OCCUPY mode, there will be a battle.

JIHAD For now, the same as WAR. In the future, JIHAD should involve some expense, and give a better fighting bonus due to fanatism in combat.

You can change your diplomatic status towards any nation you have met. They will see the change immediately. You can only change it by two degrees, so that you cannot be ALLIED, march into someone's land, and then declare WAR and occupy all their sectors.

ALLIED	gives permission to the other nation to pass through your land at a lower move cost. Also, you can put your armies in GARRISON in allied land, and they will get 1/2 of the GARRISON bonus.
TREATY	goes beyond ALLIED: if your armies or those of the other nation are involved in a battle, and the other has armies on the same sector, the two will fight together. Also, if you put your armies in GARRISON in treaty land, they will get the full GARRISON bonus.
WAR	If any army of yours is on the same sector as an enemy army, and one of the two is on ATTACK or OCCUPY mode, there will be a battle.
JIHAD	For now, the same as WAR. In the future, JIHAD should involve some expense, and give a better fighting bonus due to fanatism in combat.