On the left side of the cathedral, on practically the last part of the wall that is visible, there is a strange square formed of five Latin words carved into a slab of white marble. Arranged one work per line, these form a palindrome which reads : SATOR AREPO TENET OPERA ROTAS
Read left to right, right to left, upwards or downwards, this arrangement of letters always forms the same sentence: Sator arepo tenet opera rotas. There are some doubts about the meaning of arepo, but the two translations for the entire phrase most widely accepted are: “The Sower takes care of his plough and his work” or “The Labourer guiding the plough works by turning around.” All sorts of esoteric, religious, alchemical, numerological and cabbalistic interpretations of these sentences have been put forward: however, the hypothesis that the stone is somehow linked with the Templers became untenable when in 1936, a similar stone palindrome was found on a column on the amphitheatre of Pompeii.
Nevertheless, a Christian explanation of its origin still seems to be the most plausible one, with this square of words being used by the early Christians as a code whereby they could recognise each other. Note, for example, that the square contains a central cross made up of the word TENET, flanked at the top and bottom by the letters A and O, Alpha and Omega. What is more, one can form a cross with the 25 letters and form the words Pater noster twice, without using the A and the O twice…It could be that these palindromes or “magic squares” or “holy squares” were intended to drive the forces of evil away from the cathedral (a function similar to that of the labyrinth at the cathedral of Lucca (a posting of this is to come).
Such magic squares are to be found in about a dozen places in Italy, most notably at Campiglia Marittima outside Livorno and at the Palazzo Benciolini in Verona and in Urbino.
So next time you are in Siena, visit this magnificent Cathedral and seek out the magic square and ponder on its meaning. The Cathedral is really spectacular and it is something that most certainly should be experienced.