Trades
Kingdoms can trade goods directly to another kingdom. Each trade takes a single turn to conduct for the kingdom initiating the trade. Anything that you can sell on the Open Market can be traded to another kingdom. No more than 20% of any given item can be sent in a single trade (20% of your Fighters, 20% of your Clerics). You can also send 5 Scrolls maximum in a trade by holding down the control key while selecting them. The kingdom that you are trading too must be in your visible range.
A kingdom can receive only one trade every 100 turns it has taken starting after their first 300 turns in a 24 hour period. So a kingdom which has taken 500 turns can receive a total of 3 trades per 24 hours. After it takes another 100 turns it can receive 4 trades in a 24 hour period.
If a kingdom has been hit with an offensive attack (offensive spell, bombardement, raid, assassination, theft, military attack), it can not receive trades for two minutes. Others can also not cast barriers on that kingdom for two minutes.