Sergeant at Arms
They dont declare war against you 20 days later, it is because you force the tribute down too low. If you want better control over your tribute situation then 1) leave them with a few fiefs 2) sway their high tier lords to your side 3) and, above all else, dont press the tribute payment down too fare!Sweynfokbeard, regarding diplomacy, as I stated, I don't mind paying off the neighbor, but to pay them of just to have them declare war again 20 days later is stupid. Maybe the game should add an option to pay them extra to assure the peace lasts at least a year or something. I wouldn't always want to, but when you have 6 empires at war with you, paying one off to go away for 20 days to get his armies revitalized seems rather stupid to me. You'll still be warring at least 3 or 4 of the empires you are currently warring when he returns.
Pay them and find comfort in the fact that they will use your patronage to go pester someone else.