Sataspes, a Persian nobleman, having committed a crime punishable with death, was condemned by Xerxes to be crucified. One of his friends persuaded the monarch to commute the sentence into a voyage around Africa, which, he said, was much more severe, and might result advantageously to the nation. Sataspes obtained a vessel and recruited a crew in Egypt, and, sailing through the Pillars of Hercules, bent his course southward. He is represented as having beat about for many weeks, and probably reached the shores of the Great Saharan Desert. The aspect of this formidable and tempest-lashed coast might well appall an amateur navigator accustomed to the luxurious indolence of a Persian court. He seems to have preferred crucifixion to circumnavigation, for he at once measured back his course to the Straits. He gave an incoherent account of his adventures to Xerxes, attributing his failure to the interference of an insurmountable obstacle, the nature of which he was unable to explain. Xerxes would listen to no excuse, and ordered the original sentence to be executed forthwith. Authorities differ as to the fate of Sataspes,--one asserting that he suffered the ignominious death to which he was condemned, and another alleging that he made his escape to the island of Samos. [Illustration: THE SACRED PROMONTORY.] A colony which had been established at Massilia--now Marseilles--about six hundred years before Christ, by the Phocians, was, in the year 340 B.C., at the height of its commercial prosperity. The citizens, being desirous of extending their maritime relations, sent, at this period, upon an expedition to the North of Europe, through the Pillars of Hercules, a learned geographer and astronomer by the name of Pytheas. He started with a single ship, the finances of the city not permitting a larger outlay of means. He passed the Pillars on the sixteenth day from Massilia; and on the twentieth he arrived at the Sacred Promontory, the extreme western point of Iberia or Spain. A temple to Hercules had been erected at this spot. The inhabitants of the promontory declared, during the time of Pytheas, and, indeed, for two hundred years afterwards, that as the sun plunged at evening into the sea, they heard a hissing like that of a red-hot body suddenly dropped into water. [Illustration: PLAN OF PYTHEAS' VOYAGE.] Following the coasts of Iberia and of Celtica, he came to the point of land now known as Finisterre, in France, and the promontory Calbium. Turning to the east, he was surprised to find himself in a wide gulf, with Celtica on his right, and an immense island on his left. The gulf was the British Channel, and the island the Al-Bion that Himilcon had vaguely discerned some centuries before. It was at this point that Pytheas may be said to have begun his career; and the discovery of Great Britain may safely be attributed to him.