A conversation with Mirela Ivanova (University of Sheffield) on the creation of the Slavonic alphabet and the lives of its creators, the Byzantine missionaries Constantine-Cyril and Methodios. Despite the huge importance attributed to these men and their activities in modern scholarship, national narratives, and Slavic Orthodox identity, our knowledge about them rests largely on two texts whose interests are quite different from our own. What do we really know about them? The conversation is based on two of Mirela's articles, 'Re-thinking the Life of Constantine-Cyril the Philosopher,' Slavonic and East European Review 98 (2020) 434-463; and 'Inventing and Ethnicising Slavonic in the Long Ninth Century,' forthcoming in the Journal of Medieval History (2021).