Psalterium Sinaiticum

is a 209-folio Glagolitic Old Church Slavonic canon manuscript, the earliest Slavic psalter, dated to the 11th century.

The manuscript was found in Saint Catherine's Monastery in Egypt, after which it was named and where it remains to this day.

The major part of the psalter (177 folios) was discovered in 1850 by the Russian archimandrite Porphyrius Uspensky (Sin.

Prigotovil k pečati Sergej Sever'janov; Saint Petersburg 1922, transcribed to Cyrillic; reprinted in Graz in 1954) and by Moshe Altbauer in 1971, in a facsimile reproduction (Sinajski psaltir, glagolski rakopis od XI.

Especially inconsistent is the writing of yers and nasal vowels, and very obvious is the tendency of the vocalization of jers and the omission of epenthetic l.