Friction followed between the Kirghiz of the west and Cossack settlers, who, in common with old-established policy, had been pushed forward to occupy strips of fertile soil on the southern frontier, and the unrest was increased by the levy of a tax on the nomads, which was fiercely resented by those who rendered a nominal allegiance to Khiva. Count Perofski, who governed Orenburg, endeavoured to cope with the disturbance by constructing a chain of forts on his southern boundary, beginning with one named Alexandrovsk, on the Mangishlāk peninsula. But the Kirghiz carried their incursions far into Russian Orenburg, and plundered caravans close to Alexandrovsk. In 1839 it became clear that neither forts nor flying expeditions of Cossacks could effect the pacification of so chaotic a frontier. In Khiva the nomads found support in their attacks on Russian caravans, and a market for the sale of their prisoners and booty. There, too, hundreds of Russian subjects were held in a state of abject slavery.[539] The prestige as well as the peace of the empire was at stake. The Tsar Nicholas was not a man to brook any infringement of either, and he decided that prompt and heavy punishment should be meted out for Khivan treachery. Perofski, the governor of Orenburg, was an agent fitted by nature and training for the accomplishment of the Tsar’s designs. He equipped an army of 3½ battalions of picked infantry, 2 regiments of Ural and 5 squadrons of Orenburg Cossacks, and 22 guns with a rocket train. Transport was effected by nearly 2000 horses and 10,000 camels, tended by 2000 Kirghiz, and the utmost care was lavished on every detail of the equipment.[540] Perofski calculated on reaching his objective, a distance of 900 miles, in 50 marches, and never doubted of a triumph over the ill-trained forces of Khiva.