This dissertation explores how Englishness was imagined and used by an international community including the English, the Scots, the peoples of Scandinavia, and those of the Arabic-Islamic world during the late Middle Ages. I contend that in order to understand medieval England as a global entity, we must accept that a sense of England and Englishness arises from a transnational social imaginary among diverse national communities, and that Englishness is not only controlled by those who dwell in England but is constructed by those who perceive it simultaneously. This means, I suggest, that English national identity emerges, in different forms, out of the interplay between different ethno-national identities as they are literarily imagined. I argue that late medieval England did have a global presence, a dynamic transnational identity that finds expression in the literature of its cultural Others. But this identity was not necessarily determined by blood relationship, habit of unity, and/or shared language, as theorists of nationalism would have it. Instead, the sense of Englishness in these medieval texts is determined by the use that each culture makes of it. This dissertation, then, engages with the postcolonial theories of Homi Bhabha and Edward Said, with the borderland theories of Gloria Anzaldúa, as well as with theories of the nation as espoused by Benedict Anderson, Anthony D. Smith, and Azar Gat in order to explore the uses of Englishness as it is imagined along several different cultural axes. Drawing on cultural anthropological and new historicist approaches as well, this dissertation implicitly argues for the continued import of cultural poetics to literary study.Throughout this study, I demonstrate that the axes of Anglo-Scottish, Anglo-Scandinavian, and Anglo-Arab identities are recurrently filtered through the idealism of the genre or mode of romance, which is imaginatively and fantastically deployed to resolve the tensions between assimilation and differentiation of different ethno-national identities. Taking inspiration from medievalists such as Geraldine Heng, Kathy Lavezzo, and Patricia Clare Ingham, I explore first how the English deploy this romance mode to envision imperial ambitions: I discover the cartographically-depicted imperial advances being made on Scots in the maps of Matthew Paris and John Hardyng; I point to the memorializing of a North Sea empire between Danes and English in the romances of King Horn and Havelok the Dane; and I describe the imagining of a porousness between English and Muslim identities that lends itself to the ideal of reclaiming schismatic Muslims for Christianity in Piers Plowman, The Canterbury Tales, Mandeville's Travels, and romances such as the King of Tars and the Sowdone of Babylone . I assert that the Scots, meanwhile, attempt to navigate troubling borderland hybridity in border romances like Gologras and Sir Gawane and The Carle of Carlisle and in nationalist epics like Barbour's Brus and Blind Hary's Wallace. The Scandinavian peoples too, I suggest, nostalgically crystalize a sense of a shared Anglo-Scandinavian past in texts ranging from Saxo Grammaticus's Gesta Danorum to Egils saga to lesser studied Icelandic romances (riddarasögur) like Ála flekks saga. The Arabs, I discover, exoticize the English in their geographies in ways reflecting the Orientalizing activities of medieval Europeans, and in the late-medieval folk epic Sīrat al-Ẓāhir Baibars, Arabic-Islamic authors negotiate Englishness as a way of recovering from and confronting the threat of the crusades.In these readings, it becomes apparent that medieval writers were interested in using Englishness to navigate questions of identity through a deployment of imaginative geographies and fantasies of intercultural porousness. The plurality of these visions of English national identity, however, does not and cannot present us with a unified whole picture of a global medieval England, but it does open to us the variety of transnational experiences attached to a more widely conceived notion of national identity.