The article focuses on one of the manuscripts of the National Library in Belgrade that that was destroyed in 1941, the fourteenth-century Holiday Mine, which contained a number of unique news, as it turns out from S. Matic's additions to L. Stojanovic's catalog published in 1952. The main thing is that the cycle of Slavic alphabetic stichera in its composition, attributed by researchers to the legacy of the disciples of Cyril and Methodius, had an indication of authorship. This author is "Konstantin the Philosopher", who is reliably identified with the outstanding hymnographer Konstantin Preslavsky.