I dont know why they dont alert you about this, but make sure to keep your eye on your trade. If you establish trade with another civ in the early years, such as
You offer Ivory -------> 5 GP per turn
It will continue until you notice it. However;
You offer 5 gp per turn ------> for Ivory
The AI will definantly cancel it with you at the end of twenty turns. This can definantly burn you in the middle of the game when the AI rapes you for resources and you cant seem to keep up. Make sure to periodicaly check all Civs for "Active" treaties/agreements, and cancel the "not so lucrative" deals and make them rebid for it.
ironfang
You offer Ivory -------> 5 GP per turn
It will continue until you notice it. However;
You offer 5 gp per turn ------> for Ivory
The AI will definantly cancel it with you at the end of twenty turns. This can definantly burn you in the middle of the game when the AI rapes you for resources and you cant seem to keep up. Make sure to periodicaly check all Civs for "Active" treaties/agreements, and cancel the "not so lucrative" deals and make them rebid for it.
ironfang