During the first three centuries of Christianity, the cross was rare in Christian iconography as it depicts a purposely painful and gruesome method of public execution by impalement and/or exposure. The Ichthys, or fish symbol, was used by early Christians to covertly identify each other. The Chi-Rho monogram, which was adopted by the Constantine I in the fourth century as his banner called the labarum, was an Early Christian symbol of wider use.
Descriptions of the cross are to be found in Christian writings from the early 2nd century onwards. The Cross first became prominent in Christian imagery during the 3rd century in Egypt. A Christian bust from the site of an early church in Fayoum, Egypt, shows an ankh partially evolved, changing, over time, from a round upper section, to one that is half-way through a "morphing process", leading to the Coptic cross . It is being worn, in this half-way mode, as a necklace on the bust.