This seems to show that for freedom in the use of weapons the Greek cavalry adopted straight leg riding before they had saddle or stirrups. So far as I can learn the Hellenic seat passed on into Roman practice, but through the Dark Ages which followed the fall of Rome there seems to be no guidance as to the conduct of horsemen. Horses were not saddled in England until 631 A.D., and the first pictures we have which reveal the horsemanship of the Middle Ages are the Bayeux tapestries of the Norman Conquerors. Now for the first time horses were used by farmers to till the land. Chain mail had replaced the scale armour of the Barbarians. A perfectly straight leg locked the horseman aft against the cantle, forward against the stirrup of a weight-distributing saddle.
The war saddle
THE WAR SADDLE. During the five centuries in which body armour slowly increased in weight, and horse armour was added to the burden, the dappled woodland horse of Northern Europe was bred from strength to strength to take the growing load. So we came by our Destriérs, now known as the cart horse breeds, such as the Percheron, Cleveland Bay, and Suffolk Punch, and the heavy draught such as the Shire and Clydesdale.
Plate armour is still worn a good deal on the stage, in pageants and in military tournaments. Men used to this armour tell me that a horseman who rides less than his weight while his limbs are free, rides more than his weight when he is cramped in movement.
Suppose then that a 190 pound man in 90 pounds of armour makes a dead weight of 280 pounds. Add harness and horse armour, and the total weight is about 400 pounds. At a canter this load would certainly need a draught horse weighing not less than 1,500 pounds. Using the English saddlery one would prefer the heaviest draught animal.
Now take a load of 350 pounds in mining machinery and add 50 pounds for an apparejo pack equipment. This total dead weight of 400 pounds would make a light cargo for a 1,000 pound mule or horse, who would carry it without distress a day's march up a range of mountains.
But note well that the bearing surface of the equipment on the horse's back is about two square feet with the English saddle, and nearly eight square feet for the usual apparel of horses in heavy packing. As anybody would rather carry two buckets of water than one, because the load is halved by being properly distributed, so will the horse prefer a heavy load distributed over the whole rigid area of the ribs to a light load concentrated on a few square inches. The distribution of the load is of greater importance than its weight.
Armoured horsemen
In the days of light chain mail a special saddle was evolved with a deep seat wherein the rider was locked against the cantle by the straight thrust of his legs against box stirrups. As chain mail gave way to the heavier plate armour, the saddle bars were more and more widely padded until they covered every available inch of the rigid ribs.
Nobody seems to have noticed that with every kind of armour a chamois or buckskin lining afforded a rough-grain leather strapping for the unarmoured seat and thighs, and this gave a greasy grip against the oiled saddle.