The Altan Khans (lit. Golden Khan) ruled north-western Mongolia from about 1609 to 1691 at the latest. Altan Khan of Khalkha also known as Altan Khan of Khotogoid ruled over the Khotogoids in northwestern Mongolia and belonged to the Left Wing of the Khalkha (Eastern) Mongols. Although they claimed to be Khan, Mongolian chronicles call them Hun Taij, which was a noble rank equivalent to prince.
After the death of Dayan Khan some time after 1517 his empire was split between his descendants and became a kind of family federation. His grandson, a different Altan Khan (1507–1582) of Tumet had successful military campaigns against the Oirats. Dayan Khan's youngest son, Gersendze Huangtaizi, was given lands approximately matching the territory of present-day Mongolia. By the early 17th century most of Outer Mongolia was held by his descendants. These formed four khanates, from west to east:
The Altan Khan was important circa 1609-1682. The Tushetu Khan, with his control of the religious capital, was long the leading figure in Khalkha.
In the 17th century, to the west, the Oirat Dzungar Khanate was gradually consolidated in modern-day Xinjiang; to the north, the Russians increased their hold over the Siberian forests; and, to the east, the Manchus moved south to conquer the Ming dynasty, eventually forming the Qing dynasty.
René Grousset, 'The Empire of the Steppes, 1970