(Sator arepo tenet opera rotas). The sator-rotas square began to appear in the mid-1st century throughout the Roman Empire, initially beginning with ROTAS, later with SATOR. In the Middle Ages and the modern period, popular belief put the square on amulets and used it widely as a charm or magic formula. The five lines of five letters can each be read from all four sides and in all directions:
¶ ROTAS SATOR
OPERA AREPO
TENET TENET
AREPO OPERA
SATOR ROTAS
The interpretation is not clear. The formula is not Christian, but it has been used by Christians since the…