Emperor Keitai 継体, the fifth generation descendent of Emperor Ojin 応神 enthroned in 507 CE, has drawn interest from historians of ancient Japan for building a political power base centered in the provinces of Omi and Echizen（present day Shiga and Fukui Prefectures）. Further interest was drawn to Keitai in modern Japan, first in relation to the study of the dating of the Nihon Shoki 日本書紀（Ancient Chronicles of Japan）, then broadening into comparative issues regarding imperial burial mounds and scholarly arguments speculating over collateral blood lines within the imperial family. These latter arguments would greatly influence the fields of ancient history and archeology in postwar Japan, producing such hypotheses as the outbreak of a civil war during the reigns of Keitai and his successor Kinmei, enthroned in 539, and the disappearance of two courts from different bloodlines prior to Keitai’s enthronement.<br> On the other hand, Emperor Keitai was an important element in the promulgation of the Imperial Household Act of 1889, whose author Inoe Kowashi sought in Keitai the founder of “Japan’s unbroken line of emperors.” In other words, how to contextualize Keitai, who was enthroned by virtue of being a member of a collateral line with ten degrees of consanguinity, was a crucial issue at the time of drafting the Act.<br> In terms of how to perceive past emperors within the context of history and what kind of historical sources have been relied upon in creating the image of Japan’s emperor, Keitai is without a doubt a most suitable topic for research. And so, the author of the present article has chosen to reexamine the available sources related to Keitai, first as the beginning of a new line succession from the viewpoint of how kingship was supposed to function during the ６th century, in proposing an hypothesis for understanding overlapping reigns ruled in common by father and son.<br> The author then turns to narratives from Shinno Shoto-Ki 神皇正統記, a chronology of the 97 emperors of the Southern Court completed in 1339, in order to demonstrate the introduction of a divine aspect to imperial succession. He then cites such sources as No drama lyrics, in which women of Echizen Province yearn for Emperor Ketai, and Chinyoki 椿葉記, the Muromachi Period diary of deposed Emperor Suko 崇光 clarifying the historical particulars of his extinguished line of succession.<br> It was in this way that despite the standard historical narrative（common perception）depicting the image of Emperor Keitai in the official histories compiled in ancient Japan, different images were created through bold re-reading of the sources, rich imagination and the demands of the times. In times of crises facing imperial lines of succession, the “historical facts” about the ６th century were time and again brought to bear, as in 19th century Echizen, where one region embraced the empirical research done by scholars of national learning（kokugaku 国学）in a movement to firmly establish its historical image.<br> The author concludes by suggesting that such campaigns in which the image of Emperor Keitai has evolved and been embellished according to the perceptions of its standard bearers can be evaluated similarly to the way in which the empirical study of genealogy has played a role in preserving historical sites on which memorial inscriptions were erected, also preserving the images of those commemorated. Moreover, by flexible interpretation and citing of sources in response to the needs of particular regions and times, one way of accumulating “history,” has functioned to further deepen and reproduce the image, and a personal sense, of the emperor.