The Arab invaders called the Egyptian population qibt, which is derived
from the Greek word aigyptos and means ‘Egypt’. In the course of time the
term became narrower in meaning so that finally it was used only for the
native Christians of Egypt. The Coptic language is the demotic old Egyptian
language, mostly written in the Greek alphabet. Today it is still used in church
liturgy, but already by the tenth century the Copts were forced to use Arabic in
the mass. As a spoken language Coptic was gradually dropped and was nearly
completely replaced by Arabic by the fifteenth century. The Egyptian popular
art of the Roman and the early Arabic eras is defined as Coptic art today. It
influenced the style in which the mosques of the early Islamic era in Egypt
were built. In fact the architects of many mosques of that period, for example
the famous Ibn Tulun mosque in Cairo, were Copts. Granite or alabaster
pillars in some mosques on which Christian motifs are found show that often
churches were destroyed to acquire the valuable building material.