Lucid, enthralling and impressively expert, Saul is the perfect guide to chivalry, the medieval code that for three centuries brought a measure of honour to warfare.
The forces that propelled chivalry range from the camaraderie of horse-borne knights to Arthurian literature, but a major factor was ransom. It was more cost-effective to sell a high-born captive that to slaughter him.
The Scots, who did not adopt the principles of chivalry, were viewed as "unnaturally cruel and barbaric". By the 15th century, the deadly efficiency of the long bow put paid to restraint.