Textually the collection of Coptic manuscripts (on parchment) is linked with the Coptic papyri collection, as similar texts were in circulation written on both media; the choice of material was dependant on the resources of the community. Coptic has four principal dialects, Bohairic, Fayumic, Sahidic, and Akhmimic, most of which are represented in the Chester Beatty Collections, either as the main text or as later glosses.
The most important manuscripts were acquired by Beatty from dealers in Cairo in the 1920s. One purchase included three of five books that came from the Monastery of Apa Jeremias at Saqqara (the remaining two belong to the University of Michigan). These manuscripts (CBL Cpt 813, Cpt 814 and Cpt 815) were written in the Sahidic dialect and date from c. AD 600. They were found with Byzantine coins (minted at Alexandria in the sixth century), which help to date the deposit of the material. The bindings of these manuscripts are among the earliest surviving examples of Western binding structures, with decorated leather tooling and stamp ornament.
Thompson, Herbert (1932) The Coptic Version of the Acts of the Apostles and The Pauline Epistles in the Sahidic Dialect