thumb|right|A Sator Square (laid out in the SATOR format), etched onto a wall in the medieval fortress town of [[Oppède|Oppède-le-Vieux, France]]
The Sator Square (also called the Rotas-Sator Square or the Templar Magic Square) is a two-dimensional acrostic class of word square containing a five-word Latin palindrome.
Description and naming
thumb|right|Sator square (in ROTAS form) on the eighth-century facade of [[San Pietro ad Oratorium Abbey|Abbey of St. Peter ad Oratorium in Italy]]
The Sator square is arranged as a 5 × 5 grid consisting of five 5-letter words, thus totaling 25 characters. It uses 8 different Latin letters: 5 consonants (S, T, R, P, N) and 3 vowels (A, E, O). In some versions, the vertical and horizontal lines of the grid are also drawn, but in many cases, there are no such lines. The square is described as a two-dimensional palindrome, or word square, which is a particular class of a double acrostic.
The square comes in two forms: ROTAS (left, below), and SATOR (right, below): and some of them refer to the object as a rebus,
Discovery and dating
thumb|One of the four Sator squares (all in ROTAS form) found at [[Dura-Europos, Syria, circa AD 200.]]
thumb|The oldest known square. Found in 1936 on a column in the (CIL 8623), it is now kept in the Pompeii Museum.
The existence of the square was long recognized from early medieval times, and various examples have been found in Europe, Asia Minor, North Africa (in mainly Coptic settlements), and the Americas. In 1889, British ancient historian Francis Haverfield identified the 1868 discovery of a Sator square found in ROTAS form scratched on a plaster wall in the Roman settlement of Corinium at Cirencester to be of Roman origin; however, his assertion was discounted at the time by most academics, who considered the square to be an "early medieval charm". This discovery led Della Corte to reexamine a fragment of a square, again also in ROTAS form, that he had made in 1925 at the house of Publius Paquius Proculus, also at Pompeii (CIL IV 8123). The square at the house of Publius Paquius Proculus was dated between AD 50 and AD 79 (based on the decorative style of the interior), and the palestra square find was dated pre-AD 62 (and therefore before the earthquake of AD 62),