After the conquest of Egypt by Alexander the Great, the Greek language began to influence Egyptian writing. A new script evolved which used twentyfive letters from Greek and seven from Egyptian demotic writing (to express Egyptian sounds not found in Greek). This new writing was called Coptic.
The initial use of Coptic corresponded to the coming of Christianity and monasticism to Egypt during the fourth century CE. It was quickly adopted by the various religious communities and is the reason why many of the earliest surviving Coptic papyri are religious or monastic in nature.
By the end of the seventh century CE, Coptic had replaced Greek as the predominant language used for letters, contracts, and other documents. Greek, however, was still used for administrative purposes. Greek would continue to be used for administrative purposes until after the Arab conquest of Egypt when it would be replaced by Arabic. By the nineth century CE, Arabic had become the dominant language used throughout Egypt. Coptic, however, did not vanish. It was used by the Christian communities well into the 13th century and is still the liturgical language used by the Coptic Church.