The Dângrêk Mountains were part of the ancient Khmer Empire, which spread northwards across them, culminating with the almost complete control of the Isan area in 1220 under Jayavarman VII. Among the archaeological remains in the mountain area there are stone carvings on the "Pha Mo I-Daeng" cliff, ancient stone-cutting quarries, as well as the "Sa Trao" reservoir. There are also remains of sanctuaries that were built as homes to spirits called "phi ton nam" ('watershed spirits') in different spots along the border area of the Dângrêk mountain chain. However, the largest and most important archaeological site in these mountains is the Prasat Preah Vihear compound, a Shaivite temple of the Khmer imperial times dated from the reign of Suryavarman I in a dramatic location on top of a high hill.