Pytheas of Massilia (Ancient Greek Πυθέας ὁ Μασσαλιώτης), 4th century BC, was a Greek geographer and explorer from the Greek colony Massilia (today Marseille, France). He made a voyage of exploration to northwestern Europe possibly no earlier than around 325 BC. He may have travelled around a considerable part of Great Britain, circumnavigating it possibly between 330 and 320 BC. Pytheas is the first person on record to describe the Midnight Sun, the aurora and polar ice, the first to mention the name Britannia and Germanic tribes and the one who introduced the idea of distant "Thule" to the geographic imagination.
If one presumes that Pytheas would not have written prior to being 20 years old, he would have been a contemporary and competitor of Timaeus and Dicaearchus. As they read his writings he must have written toward the earlier years of the window.
Pytheas described his travels in a work that has not survived; only excerpts remain, quoted or paraphrased by later authors, most familiarly in Strabo's Geographica, Pliny's Natural History and the fragmentary Book V of Diodorus of Sicily's history. Most of the ancients, including the first two just mentioned, refer to his work by his name: "Pytheas says ...." Two late writers give titles: the astronomical author, Geminus of Rhodes, mentions τὰ περὶ τοῦ Ὠκεανοῦ (ta peri tou Okeanou), literally "things about the Ocean", sometimes translated as "Description of the Ocean", "On the Ocean" or "Ocean;" Marcianus, the scholiast on Apollonius of Rhodes, mentions a περίοδος γῆς (periodos gēs), a "trip around the earth" or περίπλους (periplous), "sail around."
Scholars of the 19th century tended to interpret these titles as the names of distinct works covering separate voyages; for example, Smith's Dictionary of Greek and Roman Biography and Mythology hypothesizes a voyage to Britain and Thule written about in "Ocean" and another from Cadiz to the Don river, written about in "Sail Around." As is common with ancient texts, multiple titles may represent a single source, for example, if a title refers to a section rather than the whole. The mainstream today recognizes periplus as a genre of navigational literature and concedes that there was only one work, "on the Ocean," which was based on a periplus.
Diodorus does not mention Pytheas by name. The connection is made as follows: Pliny reports that "Timaeus says there is an island named Mictis ... where tin is found, and to which the Britains cross...." Diodorus says that tin is brought to the island of Ictis, where there is an emporium. The last link is supplied by Strabo, who says that an emporium on the island of Corbulo in the mouth of the Loire was associated with with the Britain of Pytheas by Polybius. Assuming that Ictis, Mictis and Corbulo are the same, Diodorus appears to have read Timaeus, who must have read Pytheas, whom Polybius also read. An implication is that Strabo did not read Pytheas, or he would not have had to resort to Polybius.
The start of Pytheas's voyage is unknown. The Carthaginians supposedly had closed the Strait of Gibraltar to all ships from other nations. Some historians therefore believe that he traveled overland to the mouth of the Loire or the Garonne. Others believe that, to avoid the Carthaginian blockade, he may have stuck close to land and sailed only at night. It is also possible he took advantage of a temporary lapse in the blockade, known to have taken place around the time he travelled.
Strabo reports that Pytheas says he "travelled over the whole of Britain that was accessible. The word epelthein, at root "come upon", does not mean by any specific method, and Pytheas does not elaborate. He does use the word "whole" and he states a perimetron ("perimeter") of more than 40000 stadia. Using Herodotus' standard of 600 feet for one stadium obtains 4545 miles; however, there is no way to tell which standard foot was in effect. The English foot is an approximation. Strabo wants to discredit Pytheas on the grounds that 40000 stadia is outrageously high and cannot be real.
Diodorus Siculus gives a similar number: 42500 stadia (about 4830 miles) and explains that it is the perimeter of a triangle around Britain, which is roughly triangular in shape. The consensus has been that he probably took his information from Pytheas through Timaeaus. Pliny gives the circuitus reported by Pytheas as 4875 Roman miles.
The explorer, Fridtjof Nansen, in an article on the topic explains this apparent fantasy of Pytheas as a mistake of Timaeus. Strabo (and Diodorus Siculus) never saw Pytheas' work (says Nansen), but they and others read of him in Timaeus. Pytheas reported only days' sail. Timaeus converted days to stadia at the rate of 1000 per day, a standard figure of the times. However, Pytheas only sailed 560 stadia per day for a total of 23800, which in Nansen's view is consistent with 700 stadia per degree. Nansen goes on to point out that Pytheas must have stopped to obtain astronomical data; presumably, the extra time was spent ashore. Using the stadia of Diodorus Siculus, one obtains 42.5 days for the time spent in circumnavigating Britain.
The ancient perimeter according to Nansen based on the 23800 was 2375 miles. This number is in the neighborhood of what a triangular perimeter ought to be but it cannot be verified against anything Pytheas may have said nor is Diodorus Siculus very precise about the locations of the legs. The "perimeter" is often translated as "coastline" but this translation is misleading. The coastline, following all the bays and inlets, is (see Geography of the United Kingdom). Pytheas could have travelled any perimeter between that number and Diodorus'. Polybius adds that Pytheas said he traversed the whole of Britain on foot, of which he, Polybius, is skeptical. Despite Strabo's conviction of a lie, the perimeter said to have been given by Pytheas is not evidence of it. The issue of what he did say can never be settled until more fragments of Pytheas turn up.
For "Britain" Pytheas through Strabo uses Bretannikē as a feminine noun, although its form is that of an adjective: "the Britannic." Pliny uses Britannia, with Britanniae meaning all the islands, "the Britains." Diodorus has Brettanikē nēsos, "the British Island", and Brettanoi, "the British." Ptolemy has Bretania and Bretanikai nēsoi.
On the surface it would appear that Pytheas was the first to use the name, Britannia; however, manuscript variants offer a P- alternating with B- and there is good reason for thinking that the name learned by Pytheas had P-, as in *Pretania or *Pritannia, etc.: the etymology of "Britain" is so convincing that many authors use the P-form, going to far as the quote the Greek or Latin with P-, even though it is predominantly B-. They attribute the B- to replacement by the Romans in the time of Julius Caesar.
"Britain" is most like Welsh Ynys Prydein, "the island of Britain", in which is a P-Celtic allophone of Q-Celtic Cruithne in Irish Cruithen-tuath, "land of the Picts." The base word is Scottish/Irish cruth, Welsh pryd, "form." The British were the "people of forms", referring to their tattoos. The Roman word Picti, "the Picts", means "painted."
This etymology if correct suggests that Pytheas never visited Ireland or talked to the Irish, as they used the Q-Celtic, but Pytheas brought back the P-Celtic form. Furthermore, some Welsh ancestral language was spoken over all of Britain and Celtic was already divided.
Diodorus based on Pytheas reports that Britain is cold and subject to frosts, being "too much subject to the bear" (and not "under the Arctic pole" as some translations say). This report suggests that Pytheas was there in the early Spring, as he encountered frosts but not blizzards, drifts and frozen bodies of water.
The numerous population of natives, he says, live in thatched cottages, store their grain in subterranean caches and bake bread from it. They are "of simple manners" (ēthesin haplous) and are content with plain fare. They are ruled by many kings and princes who live in peace with each other. Their troops fight from chariots, as did the Greeks in the Trojan War. Until Caesar they were never beaten and never invaded.
Opposite Europe in Diodorus is the promontory (akrōtērion) of Kantion (Kent), 100 stadia (several miles) from the land, but the text is ambiguous; the land could be either Britain or the continent. Beyond by four days' sail is another promontory, Belerion, which can only be Cornwall, as Diodorus is describing the triangular perimeter and the third point is Orkas, presumably the main island of the Orkney Islands.
The inhabitants of Cornwall are involved in the manufacture of tin ingots. They mine the ore, smelt it, beat it into cubes and transport it to Ictis by wagon, which they can do at low tide. Merchants purchasing it there pack it on horses for 30 days to the Rhone river, where it is carried down to the mouth. Diodorus says that the British in Cornwall because of the tin trade are more hospitable to strangers.
Pytheas visited an island six days sailing north of Great Britain, called Thule. It has been suggested that Thule may refer to Iceland or Greenland but parts of the Norwegian coast, Shetland and Faroe Islands have also been suggested by historians. Pytheas says Thule was an agricultural country that produced honey. Its inhabitants ate fruits and drank milk, and made a drink out of grain and honey. Unlike the people from Southern Europe, they had barns, and threshed their grain there rather than outside.
He said he was shown the place where the sun went to sleep, and he noted that the night in Thule was only two to three hours. One day further north the "congealed" sea began, he claimed. As Strabo says (as quoted in Chevallier 1984):
The term used for "marine lung" (which caused much discussion in the past) actually means jellyfish, and modern scientists believe that Pytheas here tried to describe the formation of pancake ice at the edge of the drift ice, where sea, slush, and ice mix, surrounded by fog. Besides its texture, the appearance of pancake ice is perhaps reminiscent of a group of jellyfish.
After completing his survey of Great Britain, Pytheas traveled to the shallows on the continental North Sea coast. He may also have visited an island which was a source of amber and he may have sailed into the Baltic Sea to do it. According to "The Natural History" by Pliny the Elder:
Strabo uses the degrees, based on Hipparchus. Neither say that Pytheas did. Nevertheless Pytheas did obtain latitudes, which, according to Strabo, he expressed in proportions of the gnōmōn ("index"), or trigonometric tangents of angles of elevation to celestial bodies. They were measured on the gnōmōn, the vertical leg of a right triangle, and the flat leg of the triangle. The imaginary hypotenuse looked along the line of sight to the celestial body or marked the edge of a shadow cast by the vertical leg on the horizontal leg.
Pytheas took the altitude of the sun at Massilia at noon on the longest day of the year and found that the tangent was the proportion of 120 (the length of the gnōmōn) to 1/5 less than 42 (the length of the shadow). Hipparchus, relying on the authority of Pytheas (says Strabo), states that the ratio is the same as for Byzantium and that the two therefore are on the same parallel. Nansen and others prefer to give the cotangent 209/600, which is the inverse of the tangent, but the angle is greater than 45° and it is the tangent that Strabo states. His number system did not permit him to express it as a decimal but the tangent is about 2.87.
It is unlikely that any of the geographers could compute the arctangent, or angle of that tangent. Moderns look it up in a table. Hipparchos is said to have had a table of some angles. The altitude, or angle of elevation, is 70° 47’ 50″ but that is not the latitude.
At noon on the longest day the plane of longitude passing through Marseille is exactly on edge to the sun. If the Earth's axis were not tilted toward the sun, a vertical rod at the equator would have no shadow. A rod further north would have a north-south shadow, and as an elevation of 90° would be a zero latitude, the complement of the elevation gives the latitude. The sun is even higher in the sky due to the tilt. The angle added to the elevation by the tilt is known as the obliquity of the ecliptic and at that time was 23° 44′ 40″. The complement of the elevation less the obliquity is 43° 13′, only 5′ in error from Marseille's latitude, 43° 18′.
Moderns have Polaris to mark the approximate location of the North celestial pole, which it does nearly exactly, but this position of Polaris was not available in Pytheas' time, due to changes in the positions of the stars. Pytheas reported that the pole was an empty space at the corner of a quadrangle, the other three sides of which were marked by stars. Their identity has not survived but based on calculations these are believed to have been α and κ in Draco and β in Ursa Minor.
Pytheas sailed northward with the intent of locating the Arctic Circle and exploring the "frigid zone" to the north of it at the extreme of the earth. He did not know the latitude of the circle in degrees. All he had to go by was the definition of the frigid zone as the latitudes north of the line where the celestial arctic circle was equal to the celestial Tropic of Cancer, the tropikos kuklos (refer to the next subsection). Strabo's angular report of this line as being at 24° may well be based on a tangent known to Pytheas, but he does not say that. In whatever mathematical form Pytheas knew the location, he could only have determined when he was there by taking periodic readings of the elevation of the pole (eksarma tou polou in Strabo and others).
Today the declination can be obtained easily on ship with a quadrant, which, combined with the right ascension read from a watch, determines the latitude and longitude of the observer. Electronic navigational systems have made even this simple measure unnecessary. Longitude was beyond Pytheas and his peers, but it was not of as great a consequence, because ships seldom strayed out of sight of land. East-west distance was matter of contention to the geographers; they are one of Strabo's most frequent topics. Because of the gnōmōn north-south distances were accurate often to within a degree.
It is unlikely that any gnōmōn could be read accurately on the pitching deck of a small vessel at night. Pytheas must have made frequent overnight stops to use his gnōmōn and talk to the natives, which would have required interpreters, probably acquired along the way. The few fragments that have survived indicate that this material was a significant part of the periplus, possibly kept as the ship's log. There is not even a hint of native hostility; the Celts and the Germans appear to have helped him, which suggests that the expedition was put forward as purely scientific. In any case all voyages required stops for food, water and repairs; the treatment of voyagers fell under the special "guest" ethic for visitors.
The astronomic model on which ancient Greek navigation was based, which is still in place today, was already extant in the time of Pytheas, the concept of the degrees only being missing (if Hipparchus, who was after Pytheas, added those). The model divided the universe into a celestial and an earthly sphere pierced by the same poles. Each of the spheres were divided into zones (zonai) by circles (kukloi) in planes at right angles to the poles. The zones of the celestial sphere repeated on a larger scale those of the terrestrial sphere.
The basis for division into zones were the two distinct paths of the heavenly bodies: that of the stars and that of the sun and moon. Astronomers know today that the Earth revolving around the sun is tilted on its axis, bringing each hemisphere now closer to the sun (summer) now further away (winter). The Greeks had the opposite model, that the stars and the sun rotated around the earth. The stars moved in fixed circles around the poles. The sun moved at an oblique angle to the circles, which obliquity brought it now to the north, now to the south. The circle of the sun was the ecliptic. It was the center of a band called the zodiac on which various constellations were located.
The shadow cast (or not cast) by a vertical rod at noon was the basis for defining zonation. The intersection of the northernmost or southernmost points of the ecliptic defined the axial circles passing through those points as the two tropics (tropikoi kukloi, "circles at the turning points") later named for the zodiacal constellations found there, Cancer and Capricorn. During noon of the summer solstice (therinē tropē) rods there cast no shadow. The latitudes between the tropics were called the torrid zone (diakekaumenē, "burned up").
Based on their experience of the Torrid Zone south of Egypt and Libya (the Sahara desert) the Greek geographers judged it uninhabitable. Symmetry requires that there be an uninhabitable Frigid Zone (katepsugmenē, "frozen") to the north and reports from there since the time of Homer seemed to confirm it. The edge of the Frigid Zone ought to be as far south from the North Pole in latitude as the Summer Tropic is from the Equator. Strabo gives it as 24°, which may be based on a previous tangent of Pytheas, but he does not say. The Arctic Circle would then be at 66°, accurate to within a degree.
Seen from the equator the celestial North Pole (boreios polos) is a point on the horizon. As the observer moves northward the pole rises and the circumpolar stars appear, now unblocked by the Earth. At the Tropic of Cancer the radius of the circumpolar stars reaches 24°. The edge stands on the horizon. The constellation of mikra arktos (Ursa Minor, "little bear") was (and approximately still is) entirely contained within the circumpolar region. The latitude was therefore called the arktikos kuklos, "circle of the bear." The terrestrial Arctic Circle was regarded as fixed at this latitude. The celestial Arctic Circle was regarded as identical to the circumference of the circumpolar stars and therefore a variable.
When the observer is on the terrestrial Arctic Circle and the radius of the circumpolar stars is 66° the celestial Arctic Circle is identical to the celestial Tropic of Cancer. That is what Pytheas means when he says that Thule is located at the place where the Arctic Circle is identical to the Tropic of Cancer. At that point, on the day of the Summer Solstice, the vertical rod of the gnōmōn casts a shadow extending in theory to the horizon over 360° as the sun does not set. Under the pole the Arctic Circle is identical to the Equator and the sun never sets but rises and falls on the horizon. The shadow of the gnōmōn winds perpetually around it.
Based partly on data taken from Pytheas, Hipparchus correlated cubits of the sun's elevation at noon on the winter solstice, latitudes in hours of a day on the summer solstice, and distances between latitudes in stadia for some locations. Pytheas had proved that Marseille and Byzantium were on the same parallel (see above). Hipparchus (through Strabo) adds that Byzantium and the mouth of the Borysthenes (the Dnepr river) were on the same meridian and were separated by 3700 stadia (5.3° at Strabo's 700 stadia per degree). As the parallel through the river-mouth also crossed the coast of "Celtica", the distance due north from Marseille to Celtica was 3700 stadia, a baseline from which Pytheas seems to have calculated latitude and distance.
Strabo says that Ierne (Ireland) is under 5000 stadia (7.1°) north of this line. These figures place Celtica around the mouth of the Loire river, an emporium for the trading of British tin. The part of Ireland referenced is the vicinity of Belfast. Pytheas then would have crossed the Bay of Biscay from the coast of Spain to the mouth of the Loire, crossed the English channel from Brest, France to Cornwall, and traversed the Irish Sea to reach the Orkney Islands.
At noon on the winter solstice the sun stands at 9 cubits and the longest day on the summer solstice is 16 hours at the baseline through Celtica. At 2500 stadia (3.6°) north of Celtica are a people Hipparchus called Celtic but Strabo thinks are the British, a discrepancy he might not have noted if he had known that the British were also Celtic. The location is Cornwall. The sun stands at 6 cubits and the longest day is 17 hours. At 9100 stadia north of Marseille (5400 or 7.7° north of Celtica) the elevation is 4 cubits and the longest day is 18 hours. This location is in the vicinity of the Firth of Clyde.
Here Strabo launches another quibble. Hipparchus, relying on Pytheas (says Strabo), places this area south of Britain, but he, Strabo, calculates that it is north of Ierne. Pytheas, however, rightly knows what is now Scotland as part of Britain, land of the Picts, even though north of Ierne. North of southern Scotland the longest day is 19 hours. Strabo, based on theory alone, states that Ierne is so cold that any lands north of it must be uninhabited. In the hindsight given to moderns Pytheas in relying on observation in the field appears more scientific than Strabo, who discounted the findings of others merely because of their to him strangeness. The ultimate cause of his skepticism is simply that he did not believe Scandinavia could exist. This disbelief may also be the cause of alteration of Pytheas' data.
Strabo, citing Polybius, accuses Pytheas of promulgating a fictitious journey he could never have funded, as he was a private individual (idiōtēs) and a poor man (penēs). Markham proposes a possible answer to the funding question: seeing that Pytheas was known as a professional geographer and that north Europe was as yet a question mark to Massilian merchants, he suggests that "the enterprise was a government expedition of which Pytheas was placed in command." This theory is speculative but perhaps less so than Strabo's contention that Pytheas was a charlatan just because a professional geographer.
Strabo does explain his reasons for doubting Pytheas' veracity. Citing numerous instances of Pytheas apparently being far off the mark on details concening known regions, he says: "however, any man who has told such great falsehoods about the known regions would hardly, I imagine, be able to tell the truth about places that are not known to anybody. As an example he mentions that Pytheas says Kent is several days' sail from Celtica when it is visible from Gaul across the channel. If Pytheas had visited the place he should have verified it personally.
Pytheas is also a key figure in Charles Olson's Maximus Poems.