Historically, Buddhism was incorporated into Siberia in the early 17th century. Buddhism is considered to be one of Russia's traditional religions and is legally a part of Russian historical heritage. Besides the historical monastic traditions of Buryatia, Tuva and Kalmykia (the latter being the only Buddhist-majority republic in Europe), the religion of Buddhism is now spreading all over Russia, with many ethnic Russian converts. The main form of Buddhism in Russia is the Gelukpa school of Tibetan Buddhism, informally known as the "yellow hat" tradition, with other Tibetan and non-Tibetan schools as minorities. Although Tibetan Buddhism is most often associated with Tibet, it spread into Mongolia, and via Mongolia into Siberia before spreading to the rest of Russia. Datsan Gunzechoinei in Saint Petersburg is the northernmost Buddhist temple in Russia. The first evidence of the existence of Buddhism in the territory of modern Russia (more specifically Siberia, the region nearest East Asia) belongs to the 8th century AD and is associated with the state of Balhae, which in 698–926 occupied part of today's Primorye and Amur. The Mohe, a people whose culture was greatly influenced by neighboring China, Korea and Manchuria, practiced a form of Mahayana Buddhism. It initially spread into those constituent regions of Russia that are geographically or culturally adjacent to Mongolia (the area known as the Mongolian Steppe) or are inhabited by Mongolian ethnic groups: Buryatia, Zabaykalsky Krai, Tuva, and Kalmykia. The last of these was the only Buddhist region in Europe, located to the north of the Caucasus. From the earliest documented encounters with Buddhism and Buddhists, Russians had mainly negative impressions about the faith and their adherents. Conservative secular Russians and Christians regularly lambasted Buddhism, seeing it as a roadblock to the Christianization and Russification of Siberia. Russian thinkers saw Buddhism as a superstitious but advanced religion espousing the opposite of a rational and scientific worldview.