In the sixteenth century, the Buryat Mongol tribes, who were mainly shamanist but with some Buddhists of the Tibeto-Mongolian Gelug tradition, started to move from northern Mongolia to the Siberian Lake Baikal area. By the seventeenth century, Russia had conquered and made Siberia a part of their empire. In around 1712, a group of some 100 Mongolian and 50 Tibetan monks, who had been expelled from Gomang Datsan in Tibet due to an upheaval, came to Buryatia and initiated the spread of Buddhism among the Buryats.
In 1727, the border between Russia and Mongolia, which was part of the Manchu Empire, was fixed. Although pilgrimages were still allowed after this, immigration and most formal contact were stopped. The Czars supported Buddhism in order to please the Buryats and secure the borders, and used lamas to help collect taxes and gain a stronger control over the population. Thus, unlike the Kalmyks who settled in the center of Russia, the Buryats in the far eastern border area received much milder treatment by the Russians. The Russians required the Buryat’s cooperation in order to create a position of strength with which to pursue trade and influence over Manchu China. Therefore, Buddhism developed stronger and faster in Buryatia than in Kalmykia or Tuva.
In 1741 (or perhaps 1758), the first permanent datsang (monastery) was built at Tsongolsky. Three others were built shortly afterwards, the most important of which was Gusino Ozero Datsang. In order to weaken the influence of and set up a rival to the Chief Lama of Mongolia, the Bogdo Gegen Jebtsundampa Khutugtu of Urga, the Czar appointed the Abbot of Gusino Ozero as the permanent administrative and spiritual head of Transbaikalia, giving him the title Bandido Khambo Lama (Tib.: pandita mkhan-po bla-ma).
Toward the end of the eighteenth century and during the entire nineteenth century, there was great development, and all branches of Tibetan learning were introduced. There was wide pilgrimage to Tibet, whereupon many texts were brought back. Both rare Tibetan and Mongolian texts were printed mainly at the Aginsky and Tsugulsky datsangs. Within these datsangs, there were four types of colleges: tsan-nyid (debating), manba (medicine), dukor (Kalachakra) and gyu (tantra). Most datsangs, as in Mongolia, also had a dewachen a temple devoted to Amitabha, to be reborn in his pure land.
The main Kalachakra datsangs, following the lineage and style from Mongolia, which had been derived from the Namgyal Datsang at the Potala in Lhasa, Tibet, were Gusino Ozero, Aninsky, and Egetuisky. The main datsang in Mongolia from which they received it was Dechen Kalawa, founded by Gyalchen Rinpoche, which no longer exists. Aginsky followed the Kalachakra lineage and style directly from Labrang Tashi-kyil, although they used the same choga (ritual text) (sGrub-thabs mkhas-grub zhal-lung) as the other three datsangs, and this was the main place for the actual study of Kalachakra. The old lamas recall that the Leningrad Datsang probably followed the Aginsky style of Kalachakra practice, but only performed the rituals and had no actual study of it. Aginsky took all of its lineages and traditions directly from Labrang and so they used the yigcha (monastic textbooks) of Kunkhyen Jamyang Zhepa. The older lamas do think however, that Buryatia probably had all three Gelug yigchas used in Mongolia, those of Kunkhyen, Jetsunpa and Panchen, but they cannot be totally sure on this point. The best students in tsan-nyid (debating) were sent to Mongolia for further training, and the best of those went on to Tibet.
In 1917, there were 46 datsangs and dunkangs (Tib. ’dus-khang, a prayer gathering hall for laypeople), and 15,000 monks and students (Mong. quvaraγ) in Transbaikalia. Under Stalin, between 1932 and 1939, there was massive destruction of the datsangs, imprisonment of lamas, and the burning of books. The only ones standing fairly intact were Aginsky, Tsugulsky and Gusino Ozero, all in Transbaikalia, and the Leningrad Datsang. The rest lay in ruins, and some had been completely taken apart. Many of the thangkas and statues confiscated from these temples were stored in Leningrad or in an old church in Ulan Ude, which was used as a warehouse, where they remain. This old church still houses the original lifesize Tsandan Jowo, a sandalwood Buddha statue built at the time of the Buddha that was stolen by the Buryats from the Chinese in Beijing at the end of the nineteenth century, at the time of the Boxer Rebellion against foreigners.