how to crusade...

[drone]

2) You don't need to send assassins chasing around the map looking for him, instead your security forces will deal with this pesky foreigner when he crosses the border. Or if he does get through he won't last so long and will no doubt meet with an "unfortunate accident".

So the Border Fort/Counterspying function is based on the visible flag in the unit prod file? Learn something new everyday, this one goes into the wiki.

[Fagar]

The AI crusades never cease to bemuse me.

I am currently as war with the Spanish and have the provinces of Portugal and Valencia.
The Spanish have wiped out the Almohad and own all the rest of the peninsula all the way to Egypt.

The Spanish launched a crusade against the Egyptians from Castile bound for Arabia.
Now as we all know out player Crusades are required to take the shortest routes to the goal province well I wasn't too suprised when on the first turn the AI crusade attempted to march through valencia.
I denied it access and turned it away.
Next turn it moved forward into cordoba so I thought yep that is better go to your target.
Well I was most suprised when next turn it went backwards into castile, picked up more men from the high zeal province, and the following turn moved into Portugal, where by the way there is no port or current shipping lanes of any nation for the Spanish to use.
I have turned away the crusade again for it to retreat to Castile.
I haven't played for a few days but am wondering what next and is this circular crusade to continue.
I was looking for similiar experiences or insights as to how the AI is justifying it's crusade movement?

[caravel]

The crusade may be calculating distance to target based on any non blockaded shipping lanes? So perhaps the crusade is simply heading out to a port province in order to "jump" part of the journey? Thus the route calculated the year before may not exist the following year due to the shipping lanes being blockaded, ships being lost or the Spanish fleets moving around; this would cause erratic behaviour such as the AI suddenly changing it's mind on the route. Or perhaps the AI is simply not as restricted as the player...? The AI can see which moves you make when you end turn, so it would not surprise me if the AI also had more flexibility with it's crusades.