“Apart from the Eucharist and liturgies in Coptic, the most sacred symbol in the Coptic Church is the cross, including a tattooed cross on the right wrist. Originally the tattoo was an identification mark so that Coptic children would not be mistaken for Muslims in times of upheaval. In modern times the cross has become a powerful mark of Christian identity in Egypt.”

Worldmark Encyclopedia of Religious Practices, v. 1 p. 163