Twice in the history of the world has it been possible to survey a wide panorama of religions, and twice has the interest of travellers, men of science, and students of philosophy, been attracted by the immense variety of worships and beliefs. In the second century of our era the Roman Empire embraced an extraordinary range of nationalities within its sway. In the twentieth the whole history of the human race has been thrown open to the explorer, and an overwhelming mass of materials from every land confronts him. It may be worth while to take a hasty glance at the chief groups of facts that are thus disclosed, and make a sort of map of their relations. I The scientific curiosity of the ancient Greeks was early awakened, and Thales of Miletus (624-546 B.C.), chief of the seven "wise men," and founder of Greek geometry and philosophy, was believed to have studied under the priests of Egypt, as well as to have {38} visited Asia and become acquainted with the Chaldean astronomy. Still more extensive travel was attributed to his younger contemporary Pythagoras, whose varied learning was explained in late traditions by his sojourn east and west, among the Persian Magi, the Indian Brahmans, and the Druids of Gaul. The first great record of observations is contained in the History of Herodotus of Halicarnassus on the coast of Asia Minor. Born in 484 B.C., six years after Marathon, and four years old when the Greeks put Xerxes to flight at Salamis, he devoted his maturity to the record of the great international struggle. Hither and thither he passed, collecting information, an eager student of human things. In Egypt he compared the gods with those of Greece, and attempted to distinguish two sets of elements in Hellenic religion, Egyptian and Pelasgic. He left notes on the Babylonians and the Persians, on the Scythians in the vast tracts east of northern Europe, on the Getæ south of the Danube. When the conquests of Alexander the Great (356-323 B.C.) threw open the gates of Asia, a stream of travellers passed into Persia and India, whose reports were utilised by the geographers of later days. The religion of Zoroaster, whose name was already known to Plato, attracted great attention. At the court of Chandragupta on the Ganges, at the opening of the third century B.C., Megasthenes, {39} the ambassador of Seleucus (who had succeeded to the dominions of Alexander in Asia), set down brief memoranda on the usages and belief of the Hindus among whom he resided. Nearer home the representatives of Mesopotamian and Egyptian learning commended their national cultures to their conquerors. Berosus, priest of Bel in Babylon, translated into Greek a Babylonian work on astronomy and astrology, and compiled a history of his country from ancient documents; while his contemporary, Manetho, of Sebennytus in the Nile Delta, undertook a similar service for his native land.