So, I went digging around wondering just how old they are. Which is when the Square on the left, found at Pompeii popped up.
It isn't pretty, and I doubt it will protect against a volcano. However, this paper also popped up on my radar.
And so I read this:
“The formula has a long history. The earliest text was at one time thought to be a Copic papyrus of the fourth or fifth century A.D., but recent discoveries have now dated it in the Roman period. During the campaign of 1931-2, excavations at Dura-Europus on the Euphrates, conducted under Rostovtzeff by Yale University and the French Academy of Inscriptions and Letters, unearthed three specimens on the walls of a military office in what had originally been the temple of Azzanathkona. The following year a fourth was discovered, all of which must have been inscribed before the Persians destroyed Dura soon after A.D. 256. The finds at Dura vindicated a third or fourth century British specimen scratched on a fragment of wall plaster from Victoria Road, Cirencester, in Gloucestershire. Haverfield had long before attributed this to a Roman date, but his theory was discounted at the time, since no other instances were then known which could be dated before the Early Middle Ages, and because the only evidence at Cirencester was the letter forms (principally the A’s) and the general Romano-British character of the find spot. Five years after the discoveries at Dura, Della Corte, supervising excavations at Pompeii, came across a version written on a column near the amphitheatre. This discovery now led to the proper restoration of a similar, though fragmentary, example he had already published in 1929 from the house of a Publius Paquius Proculus, also at Pompeii.”
But... something else hit home:
“Knowledge of the charm was not confined to Europe. In his Arithmologia (Rome 1665) R. P. Kircher relates that on a voyage to Abyssinia he had discovered that the Ethiopians invoke their Saviour by enumerating the five nails of the Cross, namely: SADOR, ALADOR, DANET, ADERA, RODAS – clearly the five words of the square in a corrupt form. A similar usage appears in a version from a tomb near Faras in Nubia where the five words follow a Coptic phrase which has been interpreted to mean “the names of the nails of Christ’s Cross.” In the eleventh century, on the other hand, the five words were used in Abyssinia to denote the five wounds of Christ.”
I'm gonna go back to reading the paper now. Here's another, far prettier, Sator square I stole from NPR: