Medieval and early modern historiography had encouraged the integration of biblical and Gaelic chronologies, and throughout the eighteenth and nineteenth centuries Irish antiquarians, poets and romantic nationalists began to think of themselves as ‘Milesians’, the displaced descendants of a wandering Phoenician tribe. This chapter focuses on the British Israelites, a loose Protestant sect united by their belief that the Anglo-Saxon race was descended from the Lost Tribes of Israel and that biblical prophecies on the future of ‘Israel’ referred to the British Empire. The British Israelites argued that the ancient Irish king, Ollamh Fodhla, was actually the Hebrew prophet Jeremiah. This myth-history was deployed in support of the British-Israel claim that the Anglo-Saxons were the true heirs to the biblical Kingdom of David. Yet despite their fascination with the mysteries of pre-Christian Ireland, most British Israelites were arch-imperialists, staunch anti-Catholics and opponents of Irish Home Rule. The chapter explores shifting notions of British and Irish racial identity in relation to scriptural genealogy, and argues that Old Testament narratives were co-opted to serve conflicting political and religious agendas.