Pytheas of Massalia
Pytheas of Massalia ( fl. 4th century BC), was a Greek geographer and explorer from the Greek colony, Massalia (modern-day Marseilles). He made a voyage of exploration to northwestern Europe at about 325 BC.
In this voyage he travelled around and visited a considerable part of Great Britain. He is the first person on record to describe the Midnight Sun. The theoretical existence of a Frigid Zone, where the nights are very short in summer and the sun does not set at the summer solstice, was already known. Similarly, reports of a country of perpetual snow and darkness (the country of the Hyperboreans) had been reaching the Mediterranean some centuries before. Pytheas is the first known scientific visitor and reporter of the arctic, polar ice, and the Germanic tribes. He introduced the idea of distant Thule to the geographic imagination, and his account of the tides is the earliest known to suggest the moon as a cause for their production.