Here's what worked for me,it was pure luck most of the time,but I somehow managed to do it.
- Don't get attacked at the very start,somehow I got lucky because the AI Umayyad usually goes for the duchy of Galicia as soon as you un-pause the game,I had the luck of not being their first target,instead they very busy conquering south
- So they are busy in Africa,excellent take all the jewish gold and attack, go for the duchy of Navarre,if you are lucky and they are really busy conquering Mauretania and/or helping their allies (the sultan of Africa) against the Lombard holy war. You will snatch this valuable piece of land from them,or die trying.
- Why is Navarre so important? Because if you are now bordering a successful Karling kingdom you have an ally that will defend against any/all Muslim holy wars for your duchies (once again this is VERY luck oriented,as from 7 games I started since Conclave only in my Asturias game did Charlemagne manage to hold his kingdom together)
- Get yourself even formally allied to the Karlings,they should have a sister/daughter/cousin by now that you can marry to get an alliance,send your chancelor to Paris and make the franks love you,because you very much depend on them.
- By now the Umayyads tried at least two holy wars,if you were lucky the franks came and drove them back,and they learned a lesson,they are licking their wounds and even got a few civil wars going on,pray to God and go for Aragon next.
- Why Aragon,why not Leon? Because the franks are lazy to walk so far west,this is their doorstep,they just have to jump over the Pyrenees. Also if they are still successful (and on this your very existence relies) Charlemagne is already crowning himself Emperor and he will go south first,he will take Barcelona since it's de jure part of the Empire of Francia,and you have to secure these lands before he does,even if it means giving up Barcelona.
- IF you succeeded,by now the age of vikings came along,and it is already rather difficult to count on your ally,they will constantly turn their doomstacks and march from Iberia to Frisia to fight a small band of raiders,I got really frustrated at this part and had to give a couple of white peace treaties to the Sultan of Andalusia before I took Aragon and Valencia,which is your next step of course.
So if you get lucky to follow these guidelines,you have created a crescent around the Muslims in Iberia (ironic isn't it) the French got your back,and you better get theirs as well,you want to be CONSTANTLY allied to the strongest possible ruler in the Kingdom/Empire and support him whenever you can. The Umayyads won't be able to attack you (right away),they will now face loss of income (they just lost Aragon and Valencia) and civil wars due to decadence and losing wars.
There's a lot of
IFs and much of it I owe to luck,I stopped after taking Valencia,as I'm afraid of the next move...I have to take the blow right in the heart of my enemy and take one of their richest provinces,Toledo... It's still not easy to attack them,and I still rely on Francia,while they are becoming more and more unreliable. The dream that Charlemagne brought to reality is now in constant decline under his quarreling grandsons. I myself am struggling for control from within the realm,trying to keep my most powerful vassals in the family and under control.. Due to this I'm entering an age of stagnation under my current king,unable to advance further, and the Saracens are licking their wounds....
EDIT: Here's a screenshot as well,I loaded it up after a while,forgot to mention I took Leon as well,but do not plan on forming the kingdom yet,also I'm trying to keep Valencia always in the hands of my heir,this only seems right
As you can see the Umayyads are facing a rather large revolt but so is Francia,so I'm waiting for my son to inherit the kingdom,as I'm too old for some ambitious land grabbing.