Pytheas(358 av. J.-C. — 288 av. J.-C.)
Pytheas
9 min read
A Greek navigator and geographer from Massalia (Marseille), Pytheas undertook an extraordinary voyage around 325 BCE toward northern Europe, reaching the mysterious island of Thule. He was one of the first to give a scientific description of tides and the Arctic regions.
Frequently asked questions
Key Facts
- Around 325 BCE: departure from Massalia (Marseille) on an exploratory voyage toward northern Europe
- First Greek to describe the British Isles and mention the frozen sea
- Reached an island called Thule, most likely Norway or Iceland
- Observed and scientifically described the phenomenon of tides, linking them to the Moon
- His accounts, dismissed as implausible by his contemporaries, were nonetheless confirmed later on
Works & Achievements
Pytheas's principal work, recounting his great voyage to northern Europe and his geographical and astronomical observations. Lost in its entirety, it is known only through quotations in Strabo, Pliny the Elder, and Diodorus Siculus.
An astronomical study in which Pytheas determined the latitude of his hometown with remarkable precision using a gnomon. This rigorous scientific result reflects his training in the Greek mathematical tradition inherited from Eudoxus of Cnidus.
The first Greek scientific account of the powerful tides of the Atlantic Ocean and their correlation with the phases of the Moon. This remarkable insight, preserved by Pliny and Geminus, did not receive a complete physical explanation until Newton.
Pytheas was the first Greek writer to describe the phenomenon of the midnight sun in sub-polar regions, as well as the near-continuous winter nights. These observations, dismissed as implausible by his contemporaries, are today recognized as entirely accurate.
Anecdotes
During his voyage north, Pytheas described a mysterious substance he called “sea lung” (pneumôn thalassês), a mixture of water, earth, and air in which one could neither walk nor sail. Historians today believe he was most likely describing sea ice or Arctic brash ice — a strikingly accurate description for the time.
Pytheas was one of the first Greek scholars to draw a scientific connection between the tides and the Moon. He observed that the great tides along the Atlantic coastline coincided with the full moon — a discovery his contemporaries found so implausible that many refused to believe him. This insight would not find its full explanation until Newton's law of gravitation in the 17th century.
Upon his return, Pytheas was accused of being a liar by the geographer Strabo, who dismissed his accounts of frozen lands and endless nights as pure fantasy. Polybius called him a fraud. Yet his descriptions of Britain, the tides, and the midnight sun have proved remarkably accurate over the centuries.
Before setting out, Pytheas accurately calculated the latitude of Massalia using a gnomon — a simple vertical rod whose shadow he measured at noon. He arrived at a value very close to reality (43°, compared to the actual 43.3°), showing that he was first and foremost a rigorous astronomer as much as an adventurous navigator.
Pytheas was probably the first Greek to describe Britain (which he called Prettanike) and to sail around it. He noted that its inhabitants grew wheat, produced a fermented barley drink, and lived in round wooden houses. These observations constitute the earliest written accounts of the Celtic peoples of Britain.
Primary Sources
Pytheas, who has misled many people, claims to have personally traveled the whole of Britain on foot, and gives the island a circumference of more than 40,000 stades.
Pytheas reports that Thule is the northernmost known island, and that there, in summer, the sun never sets. He also mentions a coagulated sea — neither land, nor sea, nor air — which cannot be crossed on foot or by boat.
Pytheas, who sailed along the whole of Britain, says the island is triangular like Sicily and names its three main capes. Its inhabitants harvest grain in covered barns, as there is not enough sun to thresh it in the open air.
Pytheas of Massalia states that in the northernmost regions, summer nights are so short that barely two hours separate sunset from sunrise, which matches observations from subpolar zones.
Sailors from Massalia had once traveled these shores beyond the Pillars of Hercules, exploring lands no Greek before them had ever set foot on, sailing northward along the Iberian and Gallic coasts.
Key Places
A Phocaean Greek colony founded around 600 BC, Massalia was Pytheas's birthplace and the departure point for his expedition. A prosperous trading city with close ties to Gaulish peoples, it possessed an intellectual and scientific tradition that allowed Pytheas to receive his education.
A Phoenician port at the Pillars of Hercules, on the edge of the known Mediterranean world. Pytheas likely stopped here before venturing into the Atlantic Ocean, symbolically crossing the boundary between the familiar world and the unknown.
The archipelago that Pytheas was the first Greek to explore and describe systematically. He estimated its coastal perimeter, described the customs of its Celtic inhabitants, their production of tin, and their farming practices.
A mysterious island described by Pytheas as the northernmost point of his journey, six days' sail north of Britain. There, he observed the midnight sun and a frozen sea. The name Thule has since become synonymous with the ends of the earth in Western culture.
On his return journey, Pytheas likely sailed along the North Sea coastline and mentioned a region that produced amber, most probably the Baltic shores. These observations are among the earliest Greek descriptions of the Germanic peoples.
