The Sator square: a five-word enigma

SATOR AREPO TENET OPERA ROTAS: five Latin words of five letters each, arranged in a grid that reads the same in four directions. The so-called Sator square is one of the most widespread and debated inscriptions of antiquity and the Middle Ages. It is found in Roman ruins, churches, manuscripts and devotional objects, from England to Syria, and there is still no agreement on its original meaning.

The evidence from Pompeii

The oldest examples come from Pompeii, and therefore predate the eruption of AD 79. One was identified on the wall of the house of Paquius Proculus; another, discovered in 1936, was scratched on a column of the Great Palaestra. In these early versions the square begins with ROTAS, and only later did the form opening with SATOR, the best known today, prevail.

Other Roman-era examples have emerged at Dura-Europos, on the Euphrates, and at Cirencester, ancient Corinium in Roman Britain, where a fragment of wall plaster bearing the square was found in 1868. Such a wide distribution suggests that the formula circulated as a word game known across much of the empire, among soldiers and civilians alike.

What does Arepo mean

Four of the words belong to ordinary Latin: sator is the sower, tenet means “holds”, opera refers to works or labour, rotas to wheels. Arepo, however, appears nowhere else and has generated all kinds of hypotheses: a proper name, a Gaulish word for the plough, an invented word to complete the pattern. A frequently proposed translation is “the sower Arepo holds the wheels with care”, but it remains conjectural.

The Pater noster hypothesis

In the 1920s it was noticed that the twenty-five letters, rearranged, form PATERNOSTER twice in the shape of a cross around the central N, with two A's and two O's left over, which can be read as alpha and omega. The theory of a Christian origin was very successful, but the finds at Pompeii made it problematic: it is hard to document, before 79, a Latin-speaking Christian community capable of devising such an emblem.

The debate remains open. Some scholars think of a Jewish origin, others of a literary pastime with no religious content, perhaps born among soldiers or schoolboys practising with words. On this view the Christian reading came later, in the following centuries, when the Pater noster anagram seemed natural to the faithful. None of these hypotheses has, so far, decisive proof.

From wall to amulet

In the Middle Ages the square was carved in sacred places, such as the church of San Pietro ad Oratorium near Capestrano, in Abruzzo, and on the side of Siena Cathedral. In popular culture it was credited with a protective function: according to beliefs recorded in several European countries, the formula was written against fires, dog bites or diseases of livestock.

The power of the Sator lies in its perfect form rather than in any certain meaning. A grid that reads in every direction conveys an idea of closed and complete order, and so it has crossed two thousand years changing its function: writing game, Christian emblem, protective sign. Each age has found in those twenty-five letters the answer it was looking for.