Baikalia (or Baykalia) is a vague geographical term referring to the region around Lake Baikal. It is less common than the concept of Transbaikalia, the area to the east of Lake Baikal. The term Baikalia is loosely defined and has no official definition. History Early History The Baikal area has a long history of human habitation. An early, historically known tribe in the area was the Kurykans, partially forefathers of at least two ethnic groups: the Buryats and the Yakuts. Located in the former northern territory of the Xiongnu confederation, Baikalia was a theatre of the Han–Xiongnu War, where the armies of the Han dynasty pursued and defeated the Xiongnu forces from the 2nd century BC to the 1st century AD. They recorded that the lake was a "huge sea" (hanhai) and designated it the North Sea (Běihǎi) of the semimythical Four Seas. The Kurykans, a Siberian tribe who inhabited the area in the sixth century, gave it a name that translates to "much water". Later on, it was called "natural lake" (Baygal nuur) by the Buryats and "rich lake" (Bay göl) by the Yakuts. Little was known to Europeans about the lake until Russia expanded into the area in the 17th century. The first Russian explorer to reach Lake Baikal was Kurbat Ivanov in 1643. Russian conquest Russian expansion into the Buryat area around Lake Baikal in 1628–58 was part of the Russian conquest of Siberia. It was done first by following the Angara River upstream from Yeniseysk (founded 1619) and later by moving south from the Lena River. Russians first heard of the Buryats in 1609 at Tomsk. According to folktales related a century after the fact, in 1623, Demid Pyanda, who may have been the first Russian to reach the Lena, crossed from the upper Lena to the Angara and arrived at Yeniseysk. Vikhor Savin (1624) and Maksim Perfilyev (1626 and 1627–28) explored Tungus country on the lower Angara. To the west, Krasnoyarsk on the upper Yenisei was founded in 1627. A number of ill-documented expeditions explored eastward from Krasnoyarsk. In 1628, Pyotr Beketov first encountered a group of Buryats and collected yasak (tribute) from them at the future site of Bratsk. In 1629, Yakov Khripunov set off from Tomsk to find a rumored silver mine. His men soon began plundering both Russians and natives. They were joined by another band of rioters from Krasnoyarsk, but left