Around 330 BC, the Greek geographer named Pytheas set out on a voyage from the Greek colony of Massalia through the Mediterranean Sea, to explore Northern Europe. He was sent out by the merchants of his native city to find a route to the tin mines of Southern Britain.
During the journey, he circumnavigated and visited a considerable part of Great Britain. It was said that he sailed around Iberia, then up the coast of Gaul to Brittany, and eventually, reached Belerium where he explored the famous tin mines.
Pytheas was the first person to describe the midnight sun, and polar ice. He also introduced the idea of ‘Thule’ to the geographic imagination, and his account was the earliest that stated that the Moon is the cause of tides. On his return, Pytheas chronicled an account of his endeavour entitled ‘On the Ocean’.