Principal symbol of Christianity, recalling the crucifixion of Jesus. There are four basic iconogaphic representations: the crux quadrata, or Greek cross, with four equal arms; the crux immissa, or Latin cross, with a base stem longer than the other arms; the crux commissa (St. Anthony's cross), resembling the Greek letter tau (T); and the crux decussataa (St. Andrew's cross), resembling the Roman numeral 10 (X). Tradition holds that the crux immissa was used for Christ's crucifixion. Coptic Christians used the ancient Egyptian ankh. Displaying the cross was not common before Constantine I abolished crucifixion in the 4th century. A crucifix shows Christ's figure on a cross and is typical of Roman Catholicism and Eastern Orthodoxy. Making the sign of the cross with the hand may be a profession of faith, prayer, dedication, or benediction.