Throughout the ancient Mediterranean world—from Alexandria to Carthage, from the Roman port of Ostia to Corinth, and on to Palmyra in Asia Minor—in locations dotting the shores of the Black Sea and the riverbanks of what is now Hungary, we find a particular image of Isis.

She stands on the prow of a ship, holding a billowing sail in front of Her, wind filling it from behind. And yet Her own garments flow out behind Her, filled with the wind produced by Her forward momentum. Trying to be precise, if dull, in their description, archeologists simply call this image “Isis with a Sail.” But those who created these images, on gems, coins, lamps, carved reliefs, and statues, would have called Her by a different title. They might have named Her Isis Pelagia, Isis of the Seas. Or Isis Euploia…