The Tin Mines of Cornwall had been known to the Greeks and possibly the Phœnicians from the earliest times. Diodorus [7]Siculus gives a fragment from the writings of the Greek traveller Poseidonius who visited Cornwall possibly in the 3rd century B.C., which may be translated as follows: "and stamping the tin into shapes of cubes or dice, they carry it in great quantities in waggons into an island called Ictis lying off Britain, when the parts between the Island and the main land became dry land by the ebbing of the tide." It has been suggested that Ictis was St. Michael's Mount and also the Isle of Wight. It is impossible to accept the latter contention, unless we take the view which has been put forward that great changes have taken place in the depths of the channel separating the Isle of Wight from the mainland, for which we have no evidence in history or tradition. Also the Isle of Wight is not less than one hundred and fifty miles from the tin mines of Cornwall, and at the period to which we are referring the only roads that existed between the two were mere tracks, for much of the distance no doubt impassable to waggons. If it had been necessary to send Cornish tin to the Isle of Wight for transport abroad, it would naturally have been taken to one or other of the many harbours along the Cornish southern coast and transhipped by sea in the summer time. The contention in favour of St. Michael's Mount is almost equally difficult to accept. It is difficult to see what advantage could have been gained by carting the tin from the mainland to that Island, when the contiguous coast possessed several excellent natural harbours. The most probable solution to the writer seems to be that the Island of Ictis was the entire Penwith Peninsula. A walk from Marazion Station to St. Erth along the low-lying belt of marsh land makes it clear that the ocean at no very distant date must at high tide have encircled the Penwith Peninsula. In a later age it is possible that the first seeds of Christianity may have come to Britain by way of Cornwall along the trade route created by the exportation of the products of the Cornish Tin Mines to Marseilles. Foreign merchants would visit Cornwall for the purpose of purchasing tin, and numbers of foreign sailors would come to these shores in the galleys that conveyed the tin to the coast of Gaul. Under the circumstances it does not seem unreasonable to suppose that the first seeds of Christianity were in this way brought into Britain through Cornwall.