Hi Hanne,
I have been wanting to make a post here following on with the discussion but just havnt had a chance over the last few days. So ill make a quick post now and hopefully will be able to to talk some more about it over the weekend.
I have found there are many advantages and reasons too the high seat in medieval war saddles. One of them being the added advantage of increased pressure and use of seat. Being raised off the horses back, even by a few inch's allows you to sit over the horse without having to bend your legs in the same way as you do in a normal seat. This allows you to sit in a straighter up and down position and and doesnt require the lateral bend in your knee that you dont get in leg harness. Im kind of having trouble explaining that without a diagram. So if that didnt make sense ill try and explain it again
This also gives reason to the long spurs used in that period. Yes some of the spur's were just fashion, but some length to the shank of the spur is necessary to close the gap that is caused by the leg harness not allowing the lateral bend in the knee. When the leg projects straight down from the hip it creates a gap from about half way down the calf, and having the longer shank on the spur closes that gap. Its a bit like having contact on the reins. you can do it with out spurs like this, but you have to move your leg further and its not as instantaneous response as it is with the longer spur.
I have also found that having your legs closer together over the saddle (in the war saddle) puts you in a position to use your leg more effectively and with more strength, but less effort. It is kind of like the difference between having your legs a shoulder with apart, and having them wide apart. I know the Barrel width of the horse doesnt change with the saddle, but being higher up does change the angle that your legs envelop the horse. Ok, im starting to loos myself here, so i must have lost any of you reading this by now

So i think i might just try and find some pictures that can explain it better than my ramblings
Hopefully some it made some sense.
More to come soon.
Luke