The lucid account of the Moravian mission of Constantine–Cyril and Methodius that Professor Dvornik has given is a persuasive and up–to–date statement of widely accepted views. Yet scarcely a single specialist would be willing to agree unhesitatingly with all the details even in such a brief résumé of the quarter-century of relations between the emerging Slavic nations and their neighbors. Indeed, some, as his footnotes suggest, might take exception to certain of his major points.
The difficulty lies in our historical sources–in their paucity, their unclear allusions, their omissions, and, worst of all, their contradictions. First of all, so little of the ninth–century material has survived that we are dependent on the views written decades or even centuries after the events. Then, even the contemporary writings have come down to us in modified form, owing to varying amounts of recopying and editing, with inevitable distortions, omissions, reinterpretations, and interpolations.