The Codex Marianus Russian: Мариинское евангелие) is a Glagolitic fourfold Gospel Book from the late tenth- and the beginning of eleventh- century, which is (along with Codex Zographensis), one of the oldest manuscript witnesses to the Old Church Slavonic language, one of the two fourfold gospels being part of the Old Church Slavonic canon, which contain fragments written in old Serbo-Slavonic (Serbian redaction of Old-Slavonic language).
Most of the Codex (172 folios, 171 according to some sources) was discovered by Viktor Grigorovič at Mount Athos during a journey to the Balkans in 1844-45, in a hermitage belonging to the Monastery of the Holy Mother of God ( the Blessed Theotokos), and thus the manuscript was named Codex Marianus in Latin. Grigorovič took the found folios to Kazan', and after his death in 1876 the Codex was transferred to Russian State Library in Moscow where it carries the catalog number грнг 6 (M.1689). Croatian diplomat and amateur scholar Antun Mihanović acquired 2 folios (containing Matthew 5.23 - 6.16) some time before Grigorovič made his discovery, and sent it to renowned Slovene Slavist Franc Miklošič, who had them published in 1850. After Miklošič's death, the two-folio fragment was deposited in the Austrian National Library in Vienna under the catalog number Cod. Slav. 146.
The Codex was first published by Croatian Slavist Vatroslav Jagić in 1883 in Saint Petersburg as Quattuor Evangeliorum versionis palaeoslovenicae Codex Marianus Glagoliticus, transcribed in Cyrllic and with extensive philological commentary in Latin. Reprint was published in Graz in 1960.
Analysing the language of the Codex it has been ascertained that one of the scribes of the Codex came from Štokavian area, namely the one under Eastern-rite. On the basis of substitutions u - ǫ, i - y, u - vъ, e - ę etc. Jagić deduced that the manuscript could have originated on Serbian area, warns that vocalization of yers (ъ > o, ь > e), as well as the occasional disappearance of epenthetic l, suggests Macedonian (Western Bulgarian) provenience. Text of Codex especially abounds with the usage of asigmatic aorist, and very frequent is the assimilation of vowels in compound adjectival declension and present forms (-aago, -uumu instead of -aego, -uemu; -aatъ instead of -aetъ etc.).
Codex forms the base text for the scientific edition of the Slavonic gospels in the series Novum Testamentum Palaeoslovenice.
 Further reading
- V. Jagić, Quattuor Evangeliorum versionis palaeoslovenicae Codex Marianus Glagoliticus, (Berlin: Weidmann, 1883; reprint Graz: Akademsiche Druck, 1960).
- B. M. Metzger, The Early Versions of the New Testament, (Oxford: Oxford University Press, 1977), 405-406.
- Evangelium secundum Ioannem, Novum Testamentum Palaeoslovenice 1 (St. Petersburg, 1998).
- M. Garzaniti, Die altslavische Version der Evangelien, (Köln: Böhlau, 2001).
- Ђ. Трифуновић, Ка почецима српске писмености, Београд 2001
- Vaganay, Léon; Christian-Bernard Amphoux, Jenny Heimerdinger (1991). An introduction to New Testament textual criticism. Cambridge: Cambridge University Press. p. 44. ISBN 978-0-521-42493-6. Retrieved 22 November 2011. "Codex Marianus, from the beginning of the eleventh century, was also copied in Macedonia and is kept in Moscow (two leaves are in Vienna)" More than one of
- Damjanović, Stjepan (2004). Slovo iskona (in Croatian). Zagreb: Matica hrvatska. ISBN 953-150-567-5.
- Schenker, Alexander (1995). The Dawn of Slavic: An Introduction to Slavic Philology. New Haven: Yale University Press. ISBN 0-300-05846-2.