Abstract: This article explores how and why history and archaeology have been mobilised and utilised in nationalist projects in East Asia, especially in the case of the Koguryo dispute between Korea and China. Koguryo (Korean)/Gaogouli (Chinese), an ancient kingdom in the period between 37 BC and AD 668, encompassed a vast area from central Manchuria to south of Seoul. According to the “Northeast Project”, launched in China in 2002, Gaogouli was an ethnic regime in an ancient Chinese province. In contrast, Korean historians of nationalist persuasion view Koguryo as an ancestral state of the Korean historical tradition and a foundation of the national identity. Unity, continuity and coherence are claimed in both communities through invoking the history and culture of Koguryo/Gaogouli. Koguryo/Gaogouli relics which were put on the UNESCO World Heritage List in 2004 are pivotal in the contestation between China and Korea. In both, the ancient relics are held to show the distinctiveness of a national past linked to the present. This article argues that the contested history of Koguryo/Gaogouli should be examined as a site of historical hybridity between China and Korea, rather than being claimed as a site of exclusive national history.