Other quotations might be given to show that Aurelian surrounded the Rome of the empire with walls which it had not before his time. He incorporated with his wall everything that stood in his way,--tombs, aqueducts, palaces, camps, and amphitheatre. It was commenced and finished in nine years, and had twenty-two gates, nineteen of which still remain. These present walls have been in part rebuilt, repaired, and strengthened at different intervals, as occasion might require, from the time of Honorius, who improved and added to the existing gates, to that of Totila, who "resolved to raze Rome to the ground. So, of the circuit of the walls he threw down as much in different places as would amount to about a third part of the whole" (Procopius, "Bello Gothico," iii. 22). Belisarius "made hasty repairs," after which the Popes stepped in and took up the tale, and put up inscriptions, so that there should be no mistake about it. Leo IV. built the walls of the Leonine city, to protect it from the Saracens, besides repairing the Aurelian walls. The Leonine walls can still be traced, the ruins standing boldly out in the landscape at the back of the Vatican. The present wall on the Trastevere side was built by Innocent X. and Urban VIII. The complete circuit of the present walls is between twelve and thirteen miles; they contain twenty gates, ancient and modern, nine of which are closed. Whilst the Romans considered the defences of the city to be the Tigris, Euphrates, Danube, desert, and ocean, their power was at its zenith; but when for the defence of their capital it was necessary to surround it with a wall, "the decline and fall of the Roman empire" had already begun. THE GATES. In the third wall of Rome we learn from different authorities that there were in all eighteen gates, commencing from the northern point at the river bank,--Flumentana, Carmentalis or Scelerata, Catularia (afterwards Ratumena), Fontinalis, Sangualis, Salularis or Salutaris, Collina or Agonalis or Quirinalis, Viminalis, Esquilina, Mæcia or Metia, Querquetulana, Cœlimontana, Firentina, Capena, Lavernalis, Randuscula, Nævia, Trigeminia. The sites of most of these have been identified. These names are culled from various authors, no one author having given us a list of them. Pliny gives us an account of the number of the gates in his time--thirty-seven in all--which has puzzled a great many writers; but, studying them on the spot, the description of Pliny is very plain and easily to be understood. He says (iii. 9):--