Diodorus Siculus, who flourished between about 60 and about 30 BC, is supposed to have relied for his account of the geography of Britain on a lost work of Pytheas, a Greek geographer from Massalia who made a voyage around the coast of Britain near the end of the fourth century BC, searching for the source of amber. The record of the voyage of Pytheas was lost in antiquity but was known to some later writers, including Timaeus, Posidonius, and Pliny the Elder. Their work is contradictory, but from it deductions can be made about what was reported by Pytheas. No other sources concerning the tin trade in the ancient world are known. Diodorus gives an account that is generally supposed to be a description of the working of Cornish tin at about the time of the voyage of Pytheas. He says: In the Greek text of Diodorus the name appears, in the accusative case, as "Iktin", so that translators have inferred that the nominative form of the name was "Iktis", rendering this into the medieval lingua franca of Latin as "Ictis". However, some commentators doubt that "Ictis" is correct and prefer "Iktin". In Book IV of his Natural History, Pliny quotes Timaeus and refers to "insulam Mictim" : It has been suggested that "insulam Mictim" was a copying error for insulam Ictim, and Diodorus and Pliny probably both relied on the sameprimary source. However, while it is possible that "Mictim" and "Iktin" are one and the same, it is also possible that they are different places. The word "inwards" can be interpreted as meaning "towards our home", and six days' sail from Britain could take a boat to somewhere on the Atlantic coast of what is now France. Strabo, a contemporary of Diodorus, stated in his Geography that British tin was shipped from Massalia on the Mediterranean coast of Gaul. Julius Caesar, in his De Bello Gallico, says of the Veneti: "This last-named people were by far the most powerful on the coast of Armorica: they had a large fleet plying between their own ports and Britain; they knew more about the handling of ships and the science of navigation than anyone else thereabouts."
Debate
, the Elizabethan historian, took the view that the name "Ictis" was so similar to "Vectis", the Latin name for the Isle of Wight, that the two were probably the same island. The Cornish antiquary William Borlase suggested that Ictis must have been near the coast of Cornwall and could have been a general name for a peninsula there. In 1960, Gavin de Beer concluded that the most likely location of Iktin was St Michael's Mount, a tidal island near the town of Marazion in Cornwall. Apart from the effect of the tide being consistent with what is said by Diodorus, de Beer considered the other benefits of St Michael's Mount for the Britons. This identification is supported by the Roman Britain Organization. In 1972, I. S. Maxwell weighed up the competing claims of no fewer than twelve possible sites. In 1983, after excavations, the archaeologist Barry W. Cunliffe proposed the Mount Batten peninsula near Plymouth as the site of Ictis. Near the mouth of the River Erme, not far away, a shipwreck site has produced ingots of ancient tin, which indicates a trade along the coast, although dating the site is difficult and it may not belong to the Bronze Age. The assessment of Miranda Aldhouse-Green in The Celtic World was that
