Let us go over in brief detail the various objects of interest that may now be seen in the centre of Roman greatness. Numerous sources of information exist which enable us to identify these monuments, and to form some idea of what they were in their prime. Among these may be mentioned coins and medals of the emperors, with representations upon them of buildings and sculptures in the Forum; a marble stone found at Ancyra, now Angouri in Phrygia, on which is a long inscription regarding the acts and achievements of Augustus, which is of the greatest value in determining the topography of the city; the bas-reliefs on the Arch of Constantine, and on the marble screens of Trajan, recently excavated in the Forum itself, giving a view of its north-western and south-eastern ends; and the remains of the antique marble plan of Rome, now preserved in the Capitoline Museum, originally affixed to the wall of the superb Temple of Rome, and discovered in fragments in 1867 in the garden of the monastery of SS. Cosma e Damiano. We also get most valuable help in the work of identification from the Itineraries of the middle ages--especially from that of the celebrated pilgrim from Einsiedlen, Zwingli's town in Switzerland--who visited Rome in the eighth century, and left his manuscript to his own abbey, where it may still be seen. A vast apparatus of learning has been accumulated from the works of ancient classic authors by the great scholars who have written on the historical localities and buildings of the Forum, from Donati to Becker. Nibby, Canina, Ampere, Bunsen, Plattner, and Uhrlich, in their magnificent works have supplied a mine of wealth from which most subsequent writers on the Forum have enriched their descriptions.