[86] The middle part of the road was raised into a terrace which commanded the adjacent country, consisted of several strata of sand, gravel, and cement, and was paved with large stones, or, in some places near the capital, with granite.

[87] Such was the solid construction of the Roman highways, whose firmness has not entirely yielded to the effort of fifteen centuries.

They united the subjects of the most distant provinces by an easy and familiar intercourse; out their primary object had been to facilitate the marches of the legions; nor was any country considered as completely subdued, till it had been rendered, in all its parts, pervious to the arms and authority of the conqueror.

The advantage of receiving the earliest intelligence, and of conveying their orders with celerity, induced the emperors to establish, throughout their extensive dominions, the regular institution of posts.

[88] Houses were every where erected at the distance only of five or six miles; each of them was constantly provided with forty horses, and by the help of these relays, it was easy to travel a hundred miles in a day along the Roman roads.