If France and Castile are Friendly, then you want to sell Labourd otherwise you run the risk of a France Castile alliance for the majority of the game. And even if Castile and France are Rivals, selling Labourd to Narava will almost guarnetee either Aragon and France Fighting or Aragon and Castile Fighting which in turn slows down Castiles expansion.
imo a Win Win situation.![]()
If France and Castille are friendly I agree. However I don't think I've EVER seen this happen.
Also another problem I have with the AI is that they don't seem to switch alliances all that much due to the trust mechanic and rival mechanic. Really I would think it would be a good idea to let Castille become stronger so it can fight France for you, which might mean letting it ally France at the beginning. Unfortunately the AI won't ever un-ally France so...
If you want to continually hold on to Calais, fabricate trade wars on France/Burgundy and attack them before they attack you to get back Calais...with that war goal, blockading ports will give you a ticking war score, which means even if they occupy Calais, you will still have positive war score and worse case can white peace...you also then are guaranteed 5 years of truce, which means they can't attack you for that long to try and take back Calais...rinse/repeat indefinitely...
This is clever, a good use of an underused mechanic, pure reward for nearly no risk, and not so strong as to make the rest of the game pointless. Excellent.