The mutual reactions between the gun and civilization have resulted, and are still resulting, in widening the distance between the civilized and the uncivilized, placing more and more power in the hands of the civilized, and putting the uncivilized more and more into subjection by the civilized. The process that began with the invention of the fist-hammer, and was continued through the centuries by all the improvements in weapons that followed, was brought to a halt when Rome fell, and not revived until the gun came into general use in the fourteenth century. During the interval of nearly nine hundred years, civilization indeed went backward with the advance of the barbarians into Europe, checked but not wholly stopped by Charles Martel at the Battle of Tours in 732, and later by Charlemagne, his grandson, in numerous campaigns. But the gun, being adopted and improved by peoples having the mentality needed to discern its usefulness, stabilized the conditions of living afterward by keeping in check the barbarians, especially east of Europe. Its greatest single usefulness followed from this by making possible the development and utilization of the next great invention. This invention was next to the gun in point of time. It was next to the gun in influence on history also; and some people think it has had even more influence than the gun. This invention is usually called the invention of printing. Of course, printing had been invented centuries before, probably in China, and had been practiced during all the intervening centuries, in China, Egypt, Babylonia, Assyria, Greece, Rome, the Hellenistic countries and Italy. But the printing had been done from blocks on which were cut or carved many characters, that expressed whole words or sentences. Naturally, printing done from them was not adaptable to the recording of discussions, the making of connected narratives, or the publishing of books. Suddenly, about the year 1434, John Gutenberg, who lives at Mayence, conceives the idea of cutting only one letter on each block, putting the blocks in forms so arranged that the blocks can be put in such sequence as may be desired for spelling words, and all the blocks secured firmly in position. In other words, he invented movable type. Objection may be made to this statement, and the declaration urged that movable type were used in China before the Christian era. Possibly they were; some declarations have been made to that effect. But even if they were, we cannot see that their invention there had any considerable influence on history. China was separated from western Asia and from Africa and Europe by the long stretch of the dry lands of Central Asia, across which little communication passed. It is more nearly certain than most things are in ancient history, that the civilized peoples of western Asia, Africa and Europe, including Gutenberg himself, did not know of movable type until Gutenberg invented them.