The Shield Lands are a fairly recent development, politically speaking. To the outside world, there was no difference between this tract of land and the Bandit Kingdoms, and both terms were used interchangeably. That was until the "Earl" of Walworth signed on with Furyondy as a mercenary. He helped that kingdom fend off his own neighbors, and gained much of their land in the process.
He also, according to legend, received a vision from the god Mithras before a great battle with a number of bandit princes. Mithras, the god of the new religion which was only then beginning to take hold of Furyondy, told him that he could unite all of the Bandit Kingdoms under his rule if he would accept Mithras as the Highest God and spread his worship among the heathens.
He then returned with newfound military experience to his island earldom. So he started a policy of expansion, bringing several of the neighboring bandit princes under his sway. He did this mostly through conversion, as the new henotheistic religion provided an ideology that helped to unify the area. When this did not work, the Earl of Walworth would back up his ambitions with his army. He utilized heavy cavalry, i.e. knights, in a way heretofore unseen outside the armies of the Great Kingdom and Furyondy, and few of the bandit lords could stand against him. Still, he could not expand forever. Eventually his supply lines ran too thin and the rough borders of the Shield Lands were set.
The current Knight Commander, king in all but title, is the son of this conqueror. He spent most of his life consolidating the land his father gained, helping the Mithraian cult penetrate more deeply into the Shield Lands and making sure the local lords payed proper deference to him. He is now growing old, and his son will, hopefully, take the throne. Unfortunately his child is still in his minority, and the lords of the Shield Lands hunger for the times when they were more independent. Add to that the ever increasing threats from the Bandit Kingdoms and the Horned Society, and one can see that the fate of this small earldom hangs by a thread.
Still, there is hope. Many of the lords do have an ideological connection Adumnfort through their new religion. Even more importantly, Furyondy enjoys having the Shield Lands as a buffer state, and will do much to prop it up. During the reign of the current Knight Commander, Furyondy has provided troops for many attempted expeditions into the Bandit Kingdoms, and while none were too terribly successful they have helped to maintain stability within the Shield Lands itself.
Long before all this though, the Shield Lands and the Bandit Kingdoms were backwards within the Great Kingdom. Chroniclers tell that it was here that Overking Vennax the Mad had prisoners construct the terrible dungeons of Stonehell. Some say it was these prisoners who provided the stock that currently populates the area, though most within the Shield Lands would dismiss this.
Gods other than Mithras are worshiped openly within the earldom, but their cults are increasingly marginalized. The new religion, at least as practiced within the Shield Lands, is more interesting in collecting converts than murdering unbelievers. In this way they are quite different from the Theocracy of the Pale.
I'm not sure if the Shield Lands will be the focal point of a campaign within my version of Greyhawk, but I had a fairly clear idea of the area and wanted to put it down on (digital) paper. The Hold of the Sea Princes and the City of Greyhawk will possibly get some similar entries soon, unless I for some reason just become smitten with this area.
I'm still not sure what to call the Knight Commanders, but I'm thinking Almaric might be a good name as would Drogo, both of which are medieval names that sound like goofy fantasy names.