But this was removed at an early date; and in the middle ages the summit of the Arch supported the campanile of the church of St. Sergius and Bacchus that was built up against its sides. A little to the left, the road passing under the Arch joins the Clivus Capitolinus which wound through the Forum, and led up to the great Temple of Jupiter on the Capitol. The pavement of this ancient road, which still exists, is formed of broad hexagonal slabs of lava, and is as smooth and as finely jointed at this day as when the triumphal processions of the victorious Roman generals used to pass over it. At the western corner of the Arch of Severus are the scanty remains of a tall conical pyramid, about fifteen feet in diameter, which is identified as the Umbilicus Romae, placed in the exact centre of old Rome. Not far from it stood the Milliarium Aureum, or Golden Milestone, on which were inscribed all the distances of roads without the walls. The Roman roads throughout the empire terminated at this point. With this central milestone was connected that admirable system of roads which the Romans constructed in our distant island; and it is a remarkable circumstance that the principal railway lines in England are identical with the general direction of the old Roman roads. The Antonine Way is now the Great Western Railway, and the Roman Watling Street, which ran diagonally across the country from Chester in the north-west to Dover in the south-east, is now replaced by the Dover, London, Birmingham, Grand Junction, Chester, and Crewe Railways. The reason of this union of ancient and modern lines of communication is obvious. The Romans formed their roads for the purpose of transporting their armies from place to place, and at certain distances along the roads a series of military stations were established. In course of time these stations became villages, towns, and cities such as Chester, Leicester, Lancaster, Manchester. Thus, strange as it may appear, the Milliarium Aureum of the Roman Forum has had much to do with the origin of our most ancient and important towns, and with the formation of the great lines of railway that now carry on the enormous traffic between them.