It was inscribed by UNESCO in the World Heritage List as representing evolution of nomadic pastoral traditions spanning more than two millennia. (See List of World Heritage Sites in Mongolia). For many centuries, the Orkhon Valley was viewed as the seat of the imperial power of the steppes. The first evidence comes from a stone stele with runic inscriptions, which was erected in the valley by Bilge Khan, an 8th-century ruler of the Göktürk Empire. Some 25 miles to the north of the stele, in the shadow of the sacred forest-mountain Ötüken, was his Ördü, or nomadic capital. During the Qidan domination of the valley, the stele was reinscribed in three languages, so as to record the deeds of a Qidan potentate.