Poggio Bracciolini opens a new epoch in Roman topography. The ruins that had moved the superstitious wonder of the Middle Ages, that had excited Rienzi to patriotic enthusiasm, and Petrarch to reflections on the instability of human things, were now for the first time studied in a truly antiquarian spirit. Poggio read them like a book, comparing the testimony they rendered with that of Livy, Vitruvius, and Frontinus, and seeking to compile a catalogue of the existing fragments of old Rome. The first section of his treatise 'De Varietate Fortunæ,' forms by far the most important source of information we possess relating to the state of Rome in the fifteenth century.[117] It appears that the Baths of Caracalla and Diocletian could still boast of columns and marble incrustations, but that within Poggio's own recollection the marbles had been stripped from Cæcilia Metella's tomb, and the so-called Temple of Concord had been pillaged.[118] Among the ruins ascribed to the period of the Republic are mentioned a bridge, an arch, a tomb, a temple, a building on the Capitol, and the pyramid of Cestius.[119] Besides these, Poggio enumerates, as referable chiefly to the Imperial age, eleven temples, seven _thermæ_, the Arches of Titus, Severus, and Constantine, parts of the Arches of Trajan, Faustina, and Gallienus, the Coliseum, the Theatres of Pompey and Marcellus, the Circus Agonalis and Circus Maximus, the Columns of Trajan and Antonine, the two horses ascribed to Pheidias and Praxiteles, together with other marble statues, one bronze equestrian statue, and the mausoleums of Augustus and Hadrian. [Footnote 117: My references are made to the Paris edition of 1723. The first book is sometimes cited under the title of _Urbis Romæ Descriptio_.] [Footnote 118: 'Juxta viam Appiam, ad secundum lapidem, integrum vidi sepulchrum L. Cæciliæ Metellæ, opus egregium, et id ipsum tot sæculis intactum, ad calcem postea majori ex parte exterminatum' (p. 19). 'Capitolio contigua forum versus superest porticus ædis Concordiæ, quam, cum primum ad urbem accessi, vidi fere integram, opere marmoreo admodum specioso; Romani postmodum, ad calcem ædem totam et porticûs partem, disjectis columnis, sunt demoliti.' _Ibid._] [Footnote 119: Pp. 8, 9.]