Russia’s next step in advance was the outcome of the mischievous activity of the Kirghiz, a race of Mongolian origin which roams over the steppes between the Volga and the Irtish, and north of the Turkoman desert and the Ala Tau Mountains.[537] Peaceful colonisation was impossible while these restless neighbours retained their independence. Omsk and the middle course of the Irtish became Russian in 1716–1719; and for 1500 miles the Siberian frontier marched with that of tracts claimed as their own by these untamed nomads. In the reign of the Empress Anne disputes arose between the Kirghiz of the Middle and Little Hordes, who ranged over the western steppes, and their brethren of the Far East; and in 1732 the former offered submission to the empress in return for protection against their foes. Thus the Russians obtained a footing in immense tracts which were claimed by the Khānates of Khiva and Bokhārā, and a collision with their forces was rendered inevitable. The foundation of Orenburg marks a second stage in the Russian advance. It became a rendezvous for caravans between Russia and Central Asian cities, and a basis for the expeditions which followed. In 1803 the Tsar had received the allegiance of the tribes of the Mangishlāk peninsula, on the eastern shore of the Caspian. Ten years later Turkoman envoys asked help against Persia. It was refused, for Russia had her hands full with the Napoleonic wars, and a profound irritation was aroused among the savages.[538] In 1822 an ordinance was issued bringing the Little Horde within the government of Orenburg, while the western Kirghiz were made subject to that of West Siberia. These attempts to annex territories with southern boundaries so ill-defined aroused intense suspicion throughout the Khānates, and it found a vent in raids on Russian caravans. One despatched to Bokhārā was robbed in 1829 of property to the value of 500,000 roubles by Kirghiz and Khivans. The Turkoman bands, still more to be dreaded, pillaged the Bokhāran traders.