This first phase of the historic epoch, the early historic period, chronologically corresponds with the Tibetan empire or imperial period and its troubled aftermath (seventh century to the end of the tenth century CE). It was in the imperial period that the definitive introduction of Buddhism (tenpa ngadar) into Tibet, the development of the Tibetan system of writing (bö yigé), and the expansion of Tibetan political power across the entire plateau and beyond occurred. The Upper Tibetan proto-states of Zhang Zhung and Sumpa were absorbed into the pan-Bodic polity of this period as well. The vestigial period includes all archaic style monuments and rock art that continued to be founded in Upper Tibet (late tenth century to mid thirteenth century CE). The production of some archaic cultural horizon archaeological assets appears to have continued for some centuries after the collapse of imperial Tibet. Certain surveyed tombs, strongholds and religious edifices are likely to fall into this category. These architectural anachronisms seem to have been a cultural counterpoint to the inexorable process of Lamaist transformation. This period in Tibetan history is characterized by political reconsolidation, such as the formation of the Buddhist Gugé state in western Tibet in the late tenth century CE, and the ascendancy of the Sakyapa in the early thirteenth century CE.

At this juncture, the chronological values proposed above remain largely hypothetical, and with the exception of those few sites where chronometric data have been forthcoming, inexact and open to amendment. Nevertheless, this provisional chronology indicates that archaic cultural horizon archaeological monuments in Upper Tibet are a highly diverse group in terms of age and composition. By virtue of straddling the prehistoric and historic divide, the sites surveyed represent a heritage of varying environmental dimensions, social forces, religious persuasions, and political orders, which are emblematic of cultural change in Upper Tibet over a period of no less than two millennia.

This work primarily treats the typological aspects of the study of archaic monuments and rock art as the basis for their periodization. Additional study, involving the vigorous application of chronometric methodologies, will be needed to create a precise chronology for each of the monument and rock art types surveyed. It is through such study that the cultural development of Upper Tibet and the nature of its intercourse with adjoining territories will come to be known in the kind of detail that such an important piece of the world’s ancient heritage deserves. In addition to providing a model of cultural transition and adaptation in Upper Tibet, chronometric inquiry is required to determine the impacts of Late Holocene (circa 2000 BCE to present) climatic deterioration on the various archaeological sites. Material culture studies are another area of archaeological research that has barely begun. The scientific recovery and study of utilitarian and ritual objects is of the utmost importance if we are to flesh out the cultural specifications, periods of usage and environmental determinants at work at each of the sites catalogued.