From the site:
The renowned Eastern Orthodox Monastery of St. Catherine’s on Mt. Sinai was constructed by the Byzantine Emperor, Justinian I, in the late sixth century AD over the relics of the martyred saint and the place of the biblical burning bush as identified by St. Helena, the mother of the Roman Emperor, Constantine. It is home to reputedly the oldest continuously run library in existence today. Its holdings of religious and secular manuscripts are legendary and allegedly second only in number to the collection held by the Vatican: from bibles, to patristic works, to liturgies and prayers books, and on to legal documents such as deeds, court cases, Fatwahs (legal opinions). The greater proportion of the manuscripts were copied in Greek, and then in Syriac, Georgian, Coptic, Armenian, Arabic, Ottoman Turkish, and Ethiopic, as well as Old Church Slavonic.
In 1949, Kenneth W. Clark, led an expedition to the Middle East under the Auspices of the Library of Congress and its partners, to microfilm old manuscripts in various libraries of the Middle East, the largest and most isolated of which was that at St. Catherine’s. His group evaluated the 3,300 manuscripts held there and chose 1,687 for filming. Finally, the group also prepared under his direction a Checklist of Manuscripts in St. Catherine’s Monastery, Mount Sinai Microfilmed for the Library of Congress (1950), which gave researchers access to both the manuscripts microfilms and the black and white transparencies. The microfilm collection is in the custody of the Humanities and Social Sciences Division, where it still may be requested.
Since its appearance, this set has been so widely consulted by scholars around the globe that the Library has now digitized the microfilms to facilitate their use by scholars worldwide. At the same time the descriptions of the manuscripts as found in the Checklist have also been edited and updated.
Clark’s group also chose 1,284 illuminations from 113 manuscripts to be photographed in 4 x 5 inch black and white format. These have been listed on pages 22-32 of the Checklist. These have not been digitized at this time but are available to researchers in the Prints and Photographs Division of the Library of Congress.
Prints of the illuminations and microfilm reproductions of the manuscripts may be requested through our Photoduplication Service.Sample manuscripts:
Greek Manuscripts 222. Evangelion.
Syriac Manuscripts 89. Lectionary (Old Testament)
Georgian Manuscripts 30. Four Gospels
Ethiopian Manuscripts 1. Psalter and Praise of Mary
Arabic Furmans 1-48. Covenant of the Prophet and Decrees