In this favored portion of the earth, a high civilization had already been developed in the very earliest days of which we have authentic historic record. The caveman type had long disappeared and had been forgotten; people were already living in well-built cities of brick and stone. Their houses were low and flat-roofed, but the cities were surrounded with high and massive walls to protect them from enemies, and here and there within rose great square towers which were also temples. Perhaps the famous Tower of Babel was one of these, for Babel, of course, is another name for Babylon, and its people are known to have worshipped on the tops of towers, as if, by so doing, they could reach nearer to their gods. The ancient Chaldeans were religious by nature, and because the skies contained the greatest things of which they knew, they identified many of their gods with the sun, the moon, and the stars, and they worshipped these in their temples. Thus, the sun was the god _Shamash_, the moon was _Sin_, Jupiter was _Marduk_, Venus was _Ishtar_, Mars was _Nergal_, Mercury was _Nebo_, and Saturn was _Ninib_. In consequence, their priests came to give much of their time to a study of the movements of the stars. These priests, who were shrewd and learned men, discovered a great deal, but they kept their knowledge closely within the circle of their caste. Learning was not for everyone in those days because the priests posed as magicians able to interpret dreams, to explain signs, and to foretell the future. This brought them much revenue; as prophets they were not unmindful of profits. When we consider that these astrologer-astronomers did not have telescopes or our other modern instruments, it is marvelous to see how many of the laws of the heavenly bodies they really did find out for themselves. Books could be filled, with the story of their discoveries. For example, they observed that the sun slowly changed the points at which it rose and set. During certain months, the place of sunrise traveled northward, and at the same time the sun rose higher in the sky, and at noon was more nearly overhead. At this time, the days were also longer, because the sun was above the horizon more of the time, and then it was summer. During certain other months, the sun traveled south again, and all these conditions were reversed; the days grew shorter and shorter, and it was winter. This is, of course, exactly what the sun appears to do here and now, and we may observe it for ourselves. But these Babylonian priests were the first to study these phenomena and accomplish something by applying their reasoning powers to the facts that presented themselves. They took the time which was consumed in this motion from the furthest north to the furthest south and return, and from that worked out their year.