Down to the middle of the first century before Christ the British Isles were scarcely more known to the civilised nations of southern Europe than the North Pole is to the men of our own day. The trade which had probably long existed in the tin of Cornish mines had been purposely kept in mysterious darkness by the Phœnicians who profited thereby, so that Herodotus, the much inquiring, only mentions the Tin-islands (Cassiterides) to say that he knows naught concerning them. That trade had now probably become, save for the short passage of the channel, an overland one, and enriched the merchants of Marseilles. A citizen of that busy port, Pytheas by name, who seems to have been contemporary with Alexander the Great, professed to have travelled over the greater part of Britain, and afterwards to have sailed to a great distance along the northern coast of Germany. It was the fashion of later authors, such as Polybius and Strabo, to sneer at his alleged voyage of discovery and to doubt his veracity, but the tendency of modern inquiry is in some degree to restore the credit of this Marco Polo of pre-Christian times, to show that in some points he had a more correct knowledge of geography than his critics, and to deepen our regret that his work is known to us only in a few passages selected and perhaps distorted by his hostile reviewers. It must be admitted that if he reported that the circumference of Britain was 40,000 stadia (about 5,000 of our miles), and that he had traversed the whole of it on foot,[3] his statement was not altogether consistent with fact. Such, however, was all the information that the Greeks and Romans possessed concerning our island near the middle of the first century B.C., at the time when Cicero was thundering against Catiline, and Pompey was forcing his way into the temple at Jerusalem. Her time, however, for entrance on the great theatre of the world was near at hand, and it was for her a fortunate circumstance, and one not inconsistent with the part which she has played thereon in later ages, that the man who brought her on to the stage should have been himself the central figure in the world’s political history--Gaius Julius Cæsar.