Pytheas : biography
Discovery of Britain
A 1490 Italian reconstruction of the map of [[Ptolemy. The map is a result of a combination of the lines of roads and of the coasting expeditions during the first century of Roman occupation. One great fault, however, is a lopsided Scotland, which in one hypothesis is the result of Ptolemy using Pytheas’ measurements of latitude (see below).James J. Tierney; ; The Journal of Hellenic Studies, Vol. 79, (1959), pp. 132-148 Whether Ptolemy would have had Pytheas’ real latitudes at that time is a much debated issue.]]
Strabo reports that Pytheas says he "travelled over the whole of Britain that was accessible."Geographica . 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:Book V chapter 21.42500 stadia, about 4830 miles, and explains that it is the perimeter of a triangle around Britain. 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.Natural History .
The explorer Fridtjof Nansen 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 that would be spent in circumnavigating Britain. (It may have been a virtual circumnavigation; see under Thule below.)
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,Book XXXIV chapter 5, which survives as a fragment in Geographica . 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.
Name and description of the British
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. Manuscript variants however 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 so far as to 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.