Name of the phase of Egyptian language and culture which lasted from the end of the Roman Period (end of the 3rd century AD) until the coming of Islam (AD 641). This period is also called the Christian Period. In many books, the periods immediately before and after (the 3rd/4th century and the Middle Ages, respectively) are also called Coptic, and the Coptic form of Christianity (the so-called Monophysitism) still has many followers in the country. The term Coptic is derived from the Greek 'Aigyptos', 'Egypt', itself derived from ancient Egyptian 'Hwt-ka-Ptah', 'House of the 'ka' of Ptah', one of the temples in Memphis. Memphis was the residence for large parts of Egyptian history, the reason why the name of one of the temples in the city could be used as the name of the country as a whole. The Coptic script consists of the Greek alphabet supplemented by six signs derived from Demotic and used to write Egyptian sounds which for the Greek alphabet had no letters. Coptic is still used in Egypt today, but only in the Coptic church for liturgical purposes.