A lot of people have made comparisons between the pop-culture heroes of today like Marvel’s superheroes or the characters of Star Wars and the heroes of ancient Greek myth. (I’ve done it myself, here and here.) There’s a lot to be said for these comparisons in terms of narrative, but there are also interesting similarities in the way these characters are portrayed visually and sold to an admiring public.

Ancient Greek art went through an extraordinary transformation over a few centuries from the early archaic age (mid-700s BCE) to the high classical age (mid-400s BCE). One of the most telling signs of this transformation was the change in how mythic characters were represented.

Here is a scene from a Greek vase painted around 750. The human figures are highly abstracted with no individual identifying characteristics. We can make out some of what is happening in the scenes. In the upper register, a single figure lies horizontally on a table or bed surrounded by standing figures with their hands on their heads. This scene is generally interpreted as a funeral, with wailing mourners surrounding the deceased. On the lower register, warriors with shields ride in chariots. Still, for as much as we can make guesses about what is going on in these images, the details elude us. Are these generic images or are they meant to tell a story? Are the two registers even related to one another? One possibility is that this image represents the funeral for Patroclus, from the Iliad, with the funeral pyre on the upper register and the games in honor of the dead on the lower, but we have no way of knowing for sure whether that was what the artist intended or not.

This image comes from a vase painted a hundred years later, around 650 BCE. Now we have a definite story. A group of men come from the left carrying a long spear to stab the eye of a larger, seated figure on the right holding a drinking cup. Putting all these elements together, it is clear that this scene represents the blinding of Polyphemus, the giant cyclops whom Odysseus and his men got drunk before stabbing his one eye out. The scene is clear enough if you know the story, but reading the image depends on knowing the whole story and seeing the whole picture. The figures within it are not distinctive. If you took any one of the figures out and looked at it on its own, you would have no way of identifying it or guessing what story it came from.

Another century later, the ways of depicting mythic figures had developed into something new. In this vase painting, from about 540, we see figures with distinctive characteristics. On the left a robed and bearded man holds a trident: unmistakably Poseidon, god of the sea. Hermes, the messenger god, approaches him, recognizable from his broad-brimmed hat, his snake-twined herald’s staff, and the wings on his sandals. Athena comes next, indicated by her helmet and spear and the shield she carries bearing her symbol, the owl. Behind her comes Heracles, not so visible in this image but still recognizable from the bow he carries and the lion skin he wears. Even though nothing much is happening in the image—it’s just a line of people—with this combination of characters, we can tell that it is representing the story of Heracles’ ascension to join the gods on Mount Olympus. Each character, though, is distinct. You could take any one of them out of the scene, and you would still know who you were looking at.

Ancient Greek art developed a rich but understandable visual language for identifying important figures from mythology. To understand why this development mattered, we have to think about the Greeks’ place in the larger Mediterranean.

Despite the importance the modern West has accorded to ancient Greek culture, ancient Greece itself was not a powerhouse of the Mediterranean. Greece was a poor, fractious backwater compared with the great centers of wealth and culture like Egypt, Persia, and Carthage. Trade was crucial to the Greeks’ survival, which meant they had to have something to offer that other people wanted. Wine and olive oil were the major commodities the Greek traded overseas, but over time they increasingly began to export their cultural products as well. Greek artisans, poets, musicians, and actors found work throughout the Mediterranean world and beyond. The changes in how Greeks depicted myths in their art went along with their expansion into the Mediterranean’s trade networks.

Exporting culture only works if your culture can offer something the market wants. The most valuable cultural property the Greeks had was their mythology. Greek mythology was not a complete and canonical body of work to be exported whole (as I discuss here), but a flexible, malleable set of stories and characters ready to be reimagined and recombined in new and unique ways. This flexibility allowed individual Greek artists and merchants to offer their patrons and trading partners versions of myths that suited the tastes of the local market. Heracles, for instance, went over well in Etruria, and before long Etruscans were creating their own stories about the character (calling him “Herkle”) that no Greek would have imagined. The Amazons similarly found their way into Egyptian literature. Underlying it all was a set of characters (gods, heroes, monsters) with basic identifying characteristics, personalities, and stories. A Persian or Carthaginian picking up a new Greek vase in the market might not know all the myths depicted on it, but it was easy to recognize Athena’s owl or Heracles’ lion skin and begin to put together the story from there.

In a similar way, symbolic attributes have become an important part of how we identify our modern heroes. From Captain America’s shield to Luke Skywalker’s light saber, from the Doctor’s TARDIS to the house crests of Westeros, having a set of easily recognizable symbols helps us identify our favorite characters and stories at a glance. They are also great fodder for marketing merchandise—which is exactly what our ancient Greek counterparts were doing with their mythology, too. Besides being the common cultural property of a far-flung people, Greek myths and their visual representations were a brilliant marketing device that got lots of Etruscans, Romans, Egyptians, Scythians, and others to buy Greek goods.

History for Writers looks at how history can be a fiction writer’s most useful tool. From worldbuilding to dialogue, history helps you write.