Pytheas Sails to the Far North

Around 325 BCE, the Greek navigator Pytheas of Massalia (modern Marseille) undertook a voyage into the North Atlantic that carried a Mediterranean observer farther into northern Europe than any known predecessor. He sailed around Britain and reported on a distant land he called Thule. His journey matters because it produced some of the earliest firsthand Greek observations of Britain, the midnight sun, and the northern ocean, and because it sparked a debate about his reliability that has lasted more than two thousand years.

Massalia was a Greek colony founded around 600 BCE, and it prospered through trade with Gaul and beyond. Merchants there had an interest in reaching the sources of valuable goods such as tin and amber, which came from the Atlantic coasts and the North Sea region, and Carthaginian control of the Strait of Gibraltar had long limited Greek access to those waters. Pytheas was apparently skilled in astronomy and mathematics, and it is often thought that his voyage combined commercial curiosity with scientific interest. Who financed it, and exactly why, is unknown.

His own account, usually called On the Ocean, has not survived. We know it only through quotations and criticisms by later writers such as Strabo, Pliny the Elder, and Diodorus Siculus, which complicates any reconstruction. Even so, the outline is fairly clear. Pytheas seems to have traveled along the Atlantic coast, reached Britain, and circled it, estimating its size and describing its tin-producing southwest and its inhabitants. He used the sun's height with a gnomon, a simple shadow-casting instrument, to fix latitudes with notable skill.

The most famous part of his report concerns Thule, said to lie some days' sail north of Britain, where in summer the sun barely set and the sea became thick and sluggish, possibly a description of sea ice or fog. Its location is still disputed. Candidates include Iceland, Norway, and the Shetland or Orkney islands, and the evidence does not settle the question. He also mentioned a coast where amber was gathered, probably on the North Sea or Baltic shore.

Later geographers were often skeptical. Strabo called Pytheas a liar, partly because his claims seemed too fantastic, though Strabo's own reasoning was not always sound. Modern scholars generally take a more favorable view, noting that many of his descriptions match real northern phenomena. Whether or not every detail was accurate, the voyage expanded Greek knowledge of the world's northern edge, and Thule remained a symbol of the farthest north in European imagination for centuries afterward.