The Aksumite state left no king list, no annals and no dated administrative document for the sixth century. Kaleb can be placed in the 520s only through external synchronisms with the Himyar campaign, and his successors are known chiefly from coin types whose relative order is clearer than their absolute dates. Ethiopian regnal traditions assign Gebre Meskel a long reign, but those traditions are hagiographic compilations of a much later period and give figures that cannot be checked against anything. No published estimate rests on evidence rather than on the same tradition restated.
What would resolve this A dated Aksumite inscription or document naming him, an external synchronism placing his reign against a fixed event in Byzantine, Sasanian or south Arabian record, or a scientifically dated archaeological deposit stratified against his coin issues, for example radiocarbon or archaeomagnetic dates from a closed context containing coinage of the post-Kaleb sequence.
OpenAksumite archaeology and numismatics; Geez and Sabaean epigraphy; Byzantine and south Arabian documentary historyDavid W. Phillipson, Ancient Churches of Ethiopia: Fourth-Fourteenth Centuries