The ancient Greek icthus or fish (IXOYE) was used by early first-century Christians as a secret symbol. According to tradition, ancient Christians during their persecution by the Roman Empire used the fish symbol to mark meeting places and tombs or to distinguish friendfrom foe. Like the fish, an eight-spoked wheel was also used in this secret way. This ‘icthus wheel’ was made by superimposing the Greek letters Iota, Chi, Theta, Upsilon, Sigma (IXOYE) upon themselves forming the acronym early Christians used for “Jesus Christ, God’s Son, Savior”.
At every biblical city this secret sign may still be seen.