The Sator square: from Pompeii to medieval churches
SATOR AREPO TENET OPERA ROTAS: the Pompeii graffiti, the riddle of arepo, the Paternoster hypothesis and the spread of the square as a protective sign.
Five Latin words of five letters each, arranged so that they read the same in every direction: SATOR AREPO TENET OPERA ROTAS. The Sator square is the most famous palindrome of antiquity and one of the most studied riddles in archaeology. It is found scratched on Roman walls, carved on the façades of medieval churches and copied into folk remedy books until the nineteenth century, always with the same perfect structure.
The earliest evidence
The oldest examples come from Pompeii. In 1925 one was identified scratched in the House of Paquius Proculus, and in 1936 another on a column of the Great Palaestra. Since the city was buried by the eruption of Vesuvius in AD 79, these graffiti must predate that year. Other ancient examples come from Dura-Europos, in Syria, and from Cirencester, ancient Corinium, in Britain.
The literal meaning is uncertain. Sator means sower, tenet holds, opera works or with effort, rotas wheels. The word arepo appears in no other Latin text, and the proposals to explain it, from a proper name to a Gaulish loanword meaning plough, remain conjectures. A rough translation might run “the sower Arepo holds the wheels with care”, but no version is accepted by all scholars.
The Paternoster hypothesis
In 1926 the German scholar Felix Grosser observed that the twenty-five letters of the square can be rearranged into a cross formed by the word PATERNOSTER written twice, intersecting at the central N. Two As and two Os are left over, interpreted as the alpha and omega of the Book of Revelation. The discovery, made independently by others in those same years, suggested a Christian origin for the square, as a hidden sign of recognition.
The Pompeian date, however, makes the hypothesis problematic. A Christian community at Pompeii before 79, able to use the Lord's Prayer in Latin and a symbolism found in Revelation, a text most probably written after that date, seems unlikely to many. For this reason some scholars think of a Jewish origin or simply of a Roman word game, reinterpreted later in a Christian key. The debate is still open.
From churches to folk remedies
In the Middle Ages the square spread widely as a protective sign. It can be seen carved on the outer wall of Siena Cathedral, in the abbey of Valvisciolo near Sermoneta and in the church of San Pietro ad Oratorium near Capestrano, in Abruzzo. It also appears in manuscripts, on amulets and on household objects, and in popular tradition it was credited with the power to guard against fire and other dangers.
Its fortune was not confined to Latin Europe. In the Ethiopian Christian tradition the five words, in altered form, became the names of the nails of Christ's cross. In the German-speaking lands, even in the modern period, the square was painted on plates or tablets kept as a defence against fire, according to customs documented by folklorists and historians of popular traditions.
The Sator square combines wordplay, devotion and magic in exemplary fashion. Whether it began as a pastime, a hidden prayer or a protective formula, its perfect structure has fascinated generations of readers. It is one of the rare cases in which an ancient magical object has survived almost intact for nearly two thousand years, changing its meaning several times but never its form.