Pytheas (ca. 380 BC-ca. 300 BC), a Greek explorer from the city of Massalia in southern France, traveled all the way around Britain and wrote the first account of Scandinavia.

Pytheas was born in the Greek colony of Massalia on the south coast of France (now called Marseilles) in about 380 B.C. Sometime toward the end of the fourth century B.C., he was sent out by the merchants of his native city to find a route to the tin mines of southern Britain, which were the source of that valuable metal for all of Europe and the Mediterranean. The trade in tin was controlled by the Carthaginians (from the city of Carthage in present-day Tunisia), and the Greeks would have been glad to break their monopoly.

At that time, the Pillars of Hercules (the Straits of Gibraltar), the exit from the Mediterranean into the Atlantic, were controlled by the...