The fish and the ICHTHYS acrostic, sign of the early Christians

Among the earliest Christian symbols, even before the cross became established in art, a fish often appears. It is found carved on tombstones, painted in the catacombs, engraved on gems and rings. Its success was due to a linguistic coincidence cleverly exploited by Christian authors, but also to the role that fish and fishermen already had in the Gospels and, even earlier, in some cults of the Near East.

A name that is a profession of faith

In Greek, fish is ichthys, ΙΧΘΥΣ. The five letters were read as the initials of the formula Iēsous Christos Theou Yios Sōtēr, «Jesus Christ, Son of God, Saviour». Augustine, in the eighteenth book of the City of God, discusses a poem attributed to the Erythraean Sibyl whose lines form an acrostic with these words, and observes that the fish is a mystical name of Christ.

Tertullian, at the beginning of the third century, had already written in his treatise on baptism: «nos pisciculi secundum ichthyn nostrum Iesum Christum in aqua nascimur», we little fishes are born in water after our Fish, Jesus Christ. Christians were thus little fish born in the baptismal water on the model of the Fish par excellence. The image joined in a single sign the confession of faith and the sacrament of entry into the community.

Fish and fishermen in the Gospels

The symbol found support in many Gospel episodes. Jesus calls the first disciples, fishermen of the Sea of Galilee, to become «fishers of men»; he multiplies loaves and fishes to feed the crowd; after the resurrection he eats grilled fish with the disciples. At Tabgha, on the Sea of Tiberias, a famous fifth-century mosaic shows a basket of loaves between two fish, at the traditional site of the miracle.

In the Roman catacombs the fish often appears beside bread, with a clear reference to the Eucharist. In the crypts of Lucina, in the catacombs of San Callisto, a third-century fresco depicts two fish accompanied by baskets of bread. On funerary inscriptions the fish, sometimes combined with the anchor or the dove, discreetly indicated the faith of the deceased.

The inscriptions of Abercius and Pectorius

Two inscriptions are especially important. The epitaph of Abercius, bishop of Hierapolis in Phrygia who lived in the second century, recounts his travels in veiled form and says that everywhere faith gave him as food the fish from the spring, very great and pure. A fragment of the original stone, given to Pope Leo XIII by the Ottoman sultan, is now kept in the Vatican Museums.

The inscription of Pectorius, found at Autun in 1839 and datable between the fourth and sixth centuries, begins with an acrostic on the word ichthys and speaks of the divine Fish as the nourishment of the faithful. These texts show that the symbol was not merely a sign of recognition, but a true theological language, understandable to the initiated and obscure to outsiders.

The fish was not entirely new in the religious landscape of antiquity: Lucian records that the devotees of the Syrian goddess Atargatis regarded fish as sacred and did not eat them. Christianity, however, gave it a meaning entirely its own, founded on a play of letters and on a network of Gospel images, which explains why the sign has come back into use even in recent times.