Novgorod Codex
The Novgorod Codex (Russian: Новгородский кодекс, romanized: Novgorodskij kodeks) or the Novgorod Psalter (Новгородская псалтирь, Novgorodskaja psaltir') is the oldest-known book of the Kievan Rus', unearthed on 13 July 2000 in Veliky Novgorod, Russia. 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 data obtained by stratigraphy, dendrochronology, carbon dating, and from the text itself (where the year 999 occurs several times), the codex has been dated to the first quarter of the 11th century CE, and possibly the last years of the 10th century. It is therefore older than the Ostromir Gospels, the earliest precisely-dated Kievan Rus' book.