On the Cossack line, when Yermoloff assumed charge of operations, 'there was no open warfare, but there was continual unrest. No man's life was safe outside the forts and stanitzas; robbery and murder were rife; raiding parties, great and small, harried the fields, the farms and the weaker settlements.' To this state of things he was resolved to put an end. He built fortresses, pushed forward his outposts, formed moving columns of troops, and assiduously trained his soldiers to the peculiar conditions of warfare on this borderland. The Russian regiments, like the Roman legions, were often stationed in their camps or garrisons for twenty-five years; and for the service required of them their efficiency was admirable. For ten years Yermoloff carried on this tribal war with inflexible rigour, by expeditions to punish some marauding village, which was razed to the ground, and most of the men, women and children burnt or killed after defending the place with the fury of despair; by night marches to surprise and storm the hill forts; by exterminating bands of brigands; and more than once by laying deathtraps for notorious rebels or fanatics. There can be no doubt that this system of ruthless chastisement, of beating down the enemy's defences by sharp and rapid strokes, by sudden and daring inroads into the heart of their country, intimidated the tribes, and went far toward compelling them to sullen acquiescence in the Russian overlordship. Of the petty independent chiefships some were seized forcibly, others submitted and paid tribute. The Russians were advancing step by step into the interior of the country, piercing it with roads and riveting their hold on it by throwing forward their chain of connected forts. By 1820 Yermoloff appears to have convinced himself that in a few years the whole of the Caucasus--mountain and forest--would be permanently conquered and pacified; and for some time after that date there was little or no fighting, though the border was frequently disquieted by outbreaks that were sternly crushed. With the Persians and the Turks there was an interval of peace.