Social stealth in the Kingdom
The rules of social stealth in cities are pretty well understood and documented. The same cannot be said of the Kingdom. When I set out to make flag/Templar collection videos for the Kingdom, I didn't know the rules for staying Anonymous. I still don't know everything about it, but I've learned a few things along the way and wanted to share them while they're still fresh in my mind.
MEMORY BLOCKS
Informed guards and archers are added to the Kingdom at the beginning of Memory Block 4 and again in Memory Block 5 (I'm not sure if MB6 is any worse than MB5). You'll encounter an equally low level of resistance throughout MB2 and MB3. Only the northern part of the Kingdom is accessible in MB2.
Most of my Kingdom videos were shot after the first assassination in MB3. That way I had the Tackle ability (for Templars) and 5 Throwing Knives (for archers) while still facing the minimum level of guards. Only the Roman Ruins video was done in MB4 because I needed the Catch Ledge ability for flag 40.
This goes against the conventional wisdom of "do everything in Memory Block 6 because you have all your weapons and abilities". If you do the Kingdom in the second half of MB3, you won't need those weapons and abilities.
THE HORSE
The rules are different when you're on horseback. Where you would normally get away with running on foot (within 15 meters in front of an Informed guard or 5 meters behind him) you would have to Blend to remain Anonymous on the horse. Essentially, the guard's "proximity radius" increases from 1.5 meters to 15 meters when you're on the horse. You can't even walk the horse too closely behind an Informed guard.
Here's the most surprising rule I discovered: Do not accelerate to Gallop within 15 meters (in front or behind) of an Informed guard. There are many places where you can Gallop straight through without detection provided you're already at full speed. However, enter at a Run and accelerate to Gallop and you will be detected. At first I thought it was because they heard Altaïr say "Yah!" but that has nothing to do with it. The safest time to start Galloping is when your witness indicator is silent.
There's a certain asymmetry about mounting and dismounting in front of an Informed guard. You can Blend-mount (hold Blend and walk up to the horse) but I haven't found a way to Blend-dismount. Holding the Blend button while pressing Dismount doesn't work.
If your horse (i.e. the one that's following you) is standing in front of an Informed guard, I find that the fastest way to mount is to run away on foot. This coaxes the horse out into the open where it's safe to do a normal mount. Blend-mount works but it's kind of slow because you have to Blend-walk the horse away.
PLATFORM ARCHERS
The biggest pain in the Kingdom are the archers. Most are on towers but there are a few on the ground, such as those in the Roman Ruins. The thing about Kingdom archers is that they go into Open Conflict if they see you on the ground. Even if you're traveling on foot and Blending, the archers can see you.
It's still possible to sneak up on or past a tower archer. The first step is to hang back 50+ meters and get familiar with his patrol pattern. When his back is turned, run under his tower. You can do this on foot or horseback. Most archers make 90 degree turns to check their flanks. Those that don't can be safely approached from the sides.
When there are a pair of towers with archers, it's trickier because you have to wait for both to turn their backs simultaneously. For best results, wait until their patrol paterns get in phase with each other. Choose carefully which tower to assault first. If only one archer makes 90 degree turns, run under his platform (where neither archer will see you) and take him out first. If one of the archers sees you coming, attack the other one first so you can get the drop on him. In either case, you can throw a knife from the top of the first tower to the second one, provided you position yourself directly across from the remaining archer.
Starting in Memory Block 4, some towers have two or more archers each. Good luck with that. 
HIDING
There are only two types of hiding spots in the Kingdom: haystacks and benches. No roof gardens or scholars here. When hiding is necessary, I prefer to dismount the horse directly into a haystack.
Every View Point has at least one haystack nearby for the Leap of Faith. Beware of using the hay cart variety (the kind with the wooden frame) from ground level. When Unseen, the act of climbing into the hay cart will draw the attention of the View Point guards and eject you from the hay.
Originally published on forums.assassinscreed-maps.com, I'm bringing this article and a couple others over because they're frequently cited.
Excellent information there. I am not sure wheather this just happens to me or if other people have expreienced this. When I see an archer on top of a platform I instantly run over there and take him out. But, as I climb up the ladder and am about to strike he notices me and kicks me down the ladder again. Is there a quicker way to dispatch him without being exposed? Throwing knifes may work I guess but the overhang of the tower means the knife might not be able to "connect" 
What I usually do is that I stop on the ladder before reaching the top, and wait until the archer passes the ladder, so he turns his back when I climb up.
Also, it's possible to climb up the sides of the tower. They can be reached by jumping from the horseback, or sometimes on foot too.
Thanks very much 
you have been very helpful, the sides of the tower should give me a tactical advantage. Furthermore, I don't think archers are all that sharp when they are grabbed. As far as I know the only guards that perform counter grabs on Altair are high ranking ones such as Captins and Sergants. So I think I'll just throw him of the tower when we next bump into one another On a side note, Templars are outragously good fighters and always counter grab Altiar's grab attempt and give him a stern kick in the wedding veg.
Templars are EVIL and I hate them alot
Yea, templars are evil indeed.
Funny though how easily they slip and drop from the rooftop when you lure them away and they need to chase after you.
Hahaha, great idea. I usually get on there blind side or get behind them for a swift kill. Tackling a templar is extremely useful when exposed>then finish them with the hidden blade
When a Templar has spotted you, go towards him, then lock on him, after which you immediately select your hidden blade. He'll start to shout something (it's Arabic, so I don't know what it is), so you can go in for a swift exposed kill.
Wow, thanks very much!!! 
I have to try that, I love the roman ruins where all the archers are, near those huge colums. I think there is a Templar to the north and right a bit in a small alley. No time to waste
You dont even have to lock on. every templar can easily be killed by strolling up to them, waiting for them to wave their arms around and hten stab them. However I prefer to find a way to stealth air assassinate them first.
Yeah, stealth is more fun. Or a stunt assassination, like the one in Jerusalem, near the big mosque.
Ah yes, I had a go at that yesterday evening. Extremly tricky in my opinion. I leaped for the templar, yet could not quite grasp the ledge to his immediate right quick enough. I had another few goes, but ended up just doing a monk mode>assassinate.