Pytheas of Massalia (Ancient Greek: Πυθέας ὁ Μασσαλιώτης; Latin: Pitheas Massiliae; fl. 4th century BC), was a Greek geographer and explorer from the Greek colony of Massalia (modern-day Marseille). He made a voyage of exploration to northwestern Europe in about 325 BC, but his description of it, widely known in Antiquity, has not survived.