of the 16th century, the Grand Duchy of Moscow managed to conquer number of West-Siberian and Volga duchies and khanates such as Kazan Khanate, Siberia Khanate, Astrakhan Khanate, Great Nogai Horde and many others. Some of the territorial acquisitions, however, were lost during the Time of Troubles. Soon after the Time of Troubles (Treaty of Polyanovka), the Grand Duchy of Moscow was able to recover the Duchy of Smolensk (Smolensk Voivodeship) and later annex territory of Left-bank Ukraine (Truce of Andrusovo). Prior to the 18th century, the Tsardom of Russia was divided into a system of territorial units called razryads (literally order of units) as part of military reform of 1680. Moscow Razryad Sevsk Razryad Vladimir Razryad Novgorod Razryad Kazan Razryad Smolensk Razryad Ryazan Razryad Belgorod Razryad, chartered in 1658 out of the Kiev Voivodeship Tambov Razryad Tula Razryad Tobol Razryad, chartered no later than 1587 (first known Voivodeship) Tom Razryad Yenisei Razryad During the 1680s, the Tsardom of Russia acquired a substantial expansion in Transbaikal after signing the Treaty of Nerchinsk with China (Qing dynasty). By this time (at the end of the 17th century), an extensive territory from Yenisei to the Sea of Okhotsk was secured through colonization. The discovery of the Bering Strait in 1728 confirmed the eastern borders of modern Russia. The eastward advance through Siberia extended the Tobol Razryad transforming it into overstretched territory that was initially in 1708 included into Siberia Governorate. Imperial Russia Administrative reforms by Peter the Great Technically, the territorial-administrative reform started out in the Tsardom of Russia before the Imperial period. On , 1708, in order to improve the manageability of the vast territory of the state, Tsar Peter the Great issued an ukase (edict) dividing Russia into eight administrative divisions, called governorates (guberniyas), which replaced the 166 uyezds and razryads which existed before the reform: Archangelgorod Governorate Azov Governorate Ingermanland Governorate Kazan Governorate Kiev Governorate Moscow Governorate Siberia Governorate Smolensk Governorate The reform of 1708 established neither the borders of the governorates nor their internal divisions. The governorates were defined as the sets of cities and the lands adjacent to those cities. Some older subdivision types also continued to be used. Between 1710 and 1713, all governorates were subdivided into lots (), each governed by a landrat (). Every governorate was administered by an appointed governor, who also headed a board of landrats. The lots' primary purpose was fiscal,