Dragons, Fairies, and Time: Imagining the Past in Medieval Welsh, Persian, and French Narratives explores how speculative modes informed imaginative writing about the past in three medieval literary ecosystems. It begins by positing that the modern category of speculative fiction can be expanded to include the imaginative literature of the past, and that the global Middle Ages can be conceptualized not only in terms of concrete linkages but also as a particular project of identity-building occurring in parallel among disparate groups. The intersection of these categories suggests that an imaginative engagement with the past was key to medieval sociocultural formations, providing the basis for the rest of my argument. The first macro-chapter, “Past and Paradox: What Did It Mean to Time-Travel in Medieval Wales?” discusses four Middle Welsh texts—Culhwch ac Olwen, Branwen ferch Llyr, Breuddwyd Rhonabwy, and Dafydd ap Gwilym’s poem “Yr Adfail”—as representations of weirded time. In these works, characters journey into the distant past and project themselves forward to the end of the universe in ways that critique the notion of a stable and recoverable history. The second, “Hostile Others: What Did It Mean to Battle the Draconic in the Medieval Iranian World?” considers the azhdahā, a monstrous reptilian creature of Persian epic, not as an atavistic remnant of Indo-European mythology but rather as the poetic innovation of medieval poets writing in Persian. Ferdowsi, Asadi-Tusi, and Iranshāh use the azhdahā to interrogate ideas of human historical agency vis-à-vis nature, technology, and sexuality. Lastly, “Seductive Others: What Did It Mean to Love the Otherworldly in Old French Lais?” explores six of the Old French “Breton lais”—Marie de France’s Guigemar, Yonec, and Lanval, and the anonymous Tydorel, Graelent, and Guingamor. In these poems, men and women become involved in sexual liaisons with parahuman denizens of parallel worlds. These relationships insert irreducible strangeness into earthly genealogies while occulting chosen humans into zones of unattainable alterity.