As there was one government, so there was one law for all the civilized world. Local differences were not considered; the same principles of reason, justice, and humanity were believed to hold whether the Roman citizen lived upon the Euphrates or the Thames. The law of the Roman Empire is its chief legacy to posterity. Its provisions are still in force in many of the states of Europe to-day, and it is one of the subjects of study in our American universities. It exhibited a humanity unknown to the earlier legal codes. The wife, mother, and infant were protected from the arbitrary power of the head of the house, who, in earlier centuries, had been privileged to treat the members of his family as slaves. It held that it was better that a guilty person should escape than that an innocent person should be condemned. It conceived humanity, not as a group of nations and tribes, each with its peculiar institutions and legal customs, but as one people included in one great empire and subject to a single system of law based upon reason and equity. [Illustration: A Fortified Roman Gateway at Treves] [Sidenote: Roads and public works.] Magnificent roads were constructed, which enabled the messengers of the government and its armies to reach every part of the Empire with incredible speed. These highways made commerce easy and encouraged merchants and travelers to visit the most distant portions of the realm. Everywhere they found the same coins and the same system of weights and measures. Colonies were sent out to the confines of the Empire, and the remains of great public buildings, of theaters and bridges, of sumptuous villas and baths at places like Treves, Cologne, Bath, and Salzburg indicate how thoroughly the influence and civilization of Rome penetrated to the utmost parts of the territory subject to her rule. [Sidenote: The same culture throughout the Roman Empire.] The government encouraged education by supporting at least three teachers in every town of any considerable importance. They taught rhetoric and oratory and explained the works of the great writers. The Romans, who had no marked literary or artistic ability, had adopted the culture of the Greeks. This was spread abroad by the government teachers so that an educated man was pretty sure to find, even in the outlying parts of the great Empire, other educated men with much the same interests and ideas as his own. Everywhere men felt themselves to be not mere natives of this or that land but citizens of the world. [Sidenote: Loyalty to the Empire and conviction that it was eternal.]