In the first half of the eighth century, Indian craftsmen cut back a high ridge of sandstone, its back to the Beās River and the plains beyond, and carved a grand temple-complex facing northeast toward the Dhauladhar range, the first outcropping of the great Himalayan Mountains. Never completed, and damaged by successive earthquakes that sheered the stone and folded parts of the complex back into the hill, the temple at Masrur-in the modern Indian state of Himachal Pradesh-seems today half returned to its primordial condition. Its ground plan, partial section, and a roof plan, drawn by an unidentified Indian draftsman, were published in the second decade of the twentieth century, but scholarship since has neglected and misrepresented the site. It is possible to reconstruct the intention of the planning of this important complex, however, and to reposition it in a historical and symbolic context. Its creation not only marked a movement of political power into the hills in the eighth century, but also mapped cosmological power and kingship in a new way. The metaphor of temple as mountain runs throughout India's traditions of building, but, as this article demonstrates, the temple at Masrur, beyond all others from the Indian subcontinent, provides the antecedent and conceptual model for the great "temple-mountains" of Cambodia soon to be built by kings in southeast Asia.