Pytheas (Πυθέας), ca. 380 - ca. 310 BC) was a Greek merchant, geographer and explorer from the Greek colony Massilia (today Marseille, France). He made a voyage of exploration to northwestern Europe around 325 BC. He probably travelled around a considerable part of Great Britain, circumnavigating it between 330 and 320 BC. Pytheas is the first person on record to describe the Midnight Sun, the aurora and polar ice, and the first to mention the name Britannia and Germanic tribes. He may have been the first Mediterranean observer to distinguish between the Germanic and Celtic "barbarian" peoples of northern and western Europe.