Abstract Coptic, the written norm of the native language of Egypt from ca. 300 ce until ca. 1300 ce , entered into the production of private legal documents in the later sixth century ce, a domain hitherto dominated by Greek. After the Arab conquest of Egypt (642 ce ) when the use of Greek for private writing ceased, Coptic became the major language in this field and went on to maintain its leading role during the first century of the hijra . The reformation of the administrative bureaucracy by the Arab government, the formation and refinement of Islamic private law, and the advancement of Arabic literacy and education during the eighth century ce lead to an increase of private legal instruments drawn up in Arabic also by Coptic‐speaking Christian Egyptians from the ninth century ce onward.