The Sator Square is a two-dimensional acrostic class of word square containing a five-word Latin palindrome. The earliest squares were found at Roman-era sites, all in ROTAS-form, with the earliest discovery at Pompeii. The earliest square with Christian-associated imagery dates from the sixth century. By the Middle Ages, Sator squares had been found across Europe, Asia Minor, and North Africa. In 2022, the Encyclopedia Britannica called it "the most familiar lettered square in the Western world".

Dura-Europos was a Hellenistic, Parthian, and Roman border city built on an escarpment 90 metres above the southwestern bank of the Euphrates river. It is located near the village of Salhiyé, in present-day Syria. Dura-Europos was founded around 300 BC by Seleucus I Nicator, who founded the Seleucid Empire as one of the Diadochi of Alexander the Great. In 113 BC, Parthians conquered the city, and held it, with one brief Roman intermission, until 165 AD. Under Parthian rule, it became an important provincial administrative centre. The Romans decisively captured Dura-Europos in 165 AD and greatly enlarged it as their easternmost stronghold in Mesopotamia, until it was captured by the Sasanian Empire after a siege in 256–257 AD. Its population was deported, and the abandoned city eventually became covered by sand and mud and disappeared from sight.