Qingyuan Yang , Susanna F Jenkins, Geoffrey A Lerner , Clive Oppenheimer, Amy Donovan, James O S Hammond, Haiquan Wei, Jiandong Xu, Bo Pan, Ryo Nakanishi

The `Millennium Eruption’ of Changbaishan/Paektu-san Volcano, situated today on border between the People's Republic of China and Democratic People's Republic of Korea, ranks as one of the largest eruptions of the Common Era. Dated to 946 CE, its tephra deposits represent a critical marker spanning terrestrial and marine archives, as well as the glacial record of Greenland. Its geographically extensive footprint, along with the great magnitude of the eruption, have drawn wide attention from scholars working in different disciplines and representing different national and international groups. While much has been achieved through programmes of field and laboratory research, particularly sedimentological, tephrostratigraphic and petrographic studies, a universally accepted stratigraphy and timeline for the eruption episode have yet to be realised. The lack of consensus and discrepancies in interpretations of the deposits reflect, in part, the paucity and ambiguity in interpreting outcrops and historical records of the eruption, as well, arguably, as the geopolitical challenges of conducting international fieldwork in a sensitive border region. Here, we interrogate the scientific literature on the Millennium Eruption with the aims of highlighting points of contention, reconciling disparate observations where possible, and proposing new interpretations of existing data. We hope thereby to provide a clear foundation for future studies to use to build towards a coherent stratigraphic and sedimentological interpretation of the proximal tephra record, and new understanding of the compositional, stratigraphic and spatial variations of the distal deposits. Such a research agenda will lead to an improved reconstruction of this iconic volcanic eruption, which will offer wider implications for understanding the contemporary regional history and archaeology, as well as the potential environmental, ecological and climatological impacts of the eruption.