This study represents the unexpected outcome of an enquiry into the resources for the study of the medieval history of East Central Europe. While reading sources for a planned survey of medieval Poland, Bo­ hemia, Hungary, and Croatia, it became apparent to me that many current presentations of the history of Bohemia and Moravia were not based on viable evidence. Sources pertaining to the lives of Saint Cyril and Saint Methodius, as well as those for the study of Moravia, had been subjected to unwarranted interpretations or emendations, other sources of significance had been entirely omitted from considera­ tion, and finally, crucial formulations concerning Cyril and Methodius and Moravian history had been made in recent historiography without any basis in sources. Hen:e this study: an exercise in confronting the axioms of modern histori( 'graphy, philology and archaeology with the testimony of sources. My study is more of all introduction to the problems of Moravia's history than a set of fim 1 definitions and solutions. It will lead, ne­ cessarily, to a series of enquiries into the early history of several nations of East Central Europe, of the Church history of that region, and of various disciplines connected with the study of the Cyrillo-Methodian legacy.