Strabo ahead of his time by nearly 2,000 years

Chalk up another win for the ancient Greeks. The Greek historian and geographer Strabo wrote nearly 2,000 years ago that Piraeus, a small peninsula near Athens, had once been an island--and a new study in this month's issue of Geology shows he was right.

To test out whether Strabo's claim was true, researchers took sediment samples from the area. Using radiocarbon dating to determine how old different layers of the soil were and analyzing the remains of ancient microorganisms trapped in the soil, the researchers reconstructed the ancient environment of the strip connecting Piraeus to the mainland.

While Piraeus was a peninsula 8,000 years ago, the researchers found, rising sea levels had flooded the land linking it to Athens. Sure enough, by about 6,000 years ago, Piraeus was an island.

Sediment deposits turned the water between Piraeus and the mainland into a wide lagoon by 4,000 years ago, the study showed. Further deposits over the next 1,500 years turned the area into a freshwater marsh, solid enough for the Athenians to build long walls connecting their city to its harbor at Piraeus during the 5th century B.C.

It's pretty surprising that Strabo would know this about the peninsula's past. Unlike the social or political changes often noted by historians, geological changes tend to happen on timescales too long for humans to observe, much less remember. At a time when historical records were less than reliable--the ancient Greek historian Herodotus is called both "the father of history," for his careful research methods, and "the father of lies," for the many, many inaccuracies in his works--how did Strabo get this right?

One possibility, the researchers say, is that the Piraeus's history stuck around in the Athenian collective consciousness for millennia, thanks to oral tradition. The peninsula's name, too, hints at its past: "Piraeus" comes from a word meaning "beyond" or "on the other side." Strabo may have listened to people's stories, done a bit of etymology, and started writing.

Another hypothesis is that Strabo, looking out over the unusually flat landscape with his trained geographer's eye, picked out clues to the past. Strabo knew about the long walls built five hundred years before, and could likely have seen the traces of the freshwater marsh that once filled much of the peninsula. While he couldn't have known exactly when Piraeus was an island, he might have deduced that water once separated it from the mainland.