The Novgorod Codex (Russian: Новгородский кодекс) is the oldest book of Rus’, unearthed on July 13, 2000 in Novgorod. It is a palimpsest consisting of three bound wooden tablets containing four pages filled with wax, on which its former owner wrote down dozens, probably hundreds of texts during two or three decades, each time wiping out the preceding text.
According to the data obtained by stratigraphy (and dendrochronology), carbon dating and from the text itself (where the year 999 occurs several times), the wax codex was used in the first quarter of the 11th century and maybe even in the last years of the 10th century. It is therefore older than the Ostromir Gospels, the earliest precisely dated East Slavic book.
Read more about Novgorod Codex: Discovery and Description, Basic Text, Language, Preservation and Reading Method, Concealed Texts and Identity of The Owner, List of Texts