Moreover, the book The Cambridge Medieval History states: “It is easy to imagine that [Cyril] had others to help him, who must have been in the first instance people of native Slav origin with a Greek education.
Raamatus „The Cambridge Medieval History ” öeldakse veel:„ Ilmselt aitasid [Kyrillost] teised, kes olid esiteks slaavi päritoluga ning peale selle saanud ka kreeka haridust.