Founded in 1639 as a yurt monastery, Ulaanbaatar, originally '''Örgöö''' (palace-yurt), was first located at Lake Shireet Tsagaan nuur ( directly east of the imperial capital Karakorum) in what is now Burd sum, Övörkhangai, around  south-west from the present site of Ulaanbaatar, and was intended by the Mongol nobles to be the seat of Zanabazar, the first Jebtsundamba Khutughtu. Zanabazar returned to Mongolia from Tibet in 1651, and founded seven ''aimags'' (monastic departments) in Urga, later establishing four more.