The language of this valuable monument presents the Preslav literary norm of the tenth centu-ry and it is considered the basis of classic Old Church Slavonic because of both its size and the fact that it contains texts otherwise unattested in Old Church Slavonic. The codex is thus the main source for studying the language, writing, and culture of Bulgaria in the Preslav pe-riod. Our selection of this manuscript as the focus of our corpus reflects the uniqueness of the resource, and at the same time increases awareness of the significance of preserving the col-lective memory and providing access to valuable documents.