Congratulations, by building a Consulate and granting a trade subsidy,  you have become the favored trade partner of a Minor Nation and completed Episode 11.

The inter-dependency of trade and diplomatic success will be a recurring theme during your rule. The long term purpose of diplomacy is getting other countries to choose to join your Empire. But the short term goal is to gain a steady trade supply of the resources that the other nation produces. 

Once you have become the favorite trading partner of a minor nation, you can count on trade offers each turn. This is especially useful at the beginning of the game when your own nation has not yet developed its transport network.