We will briefly glance through the testimony of the “Itineraries” on this point, touching upon each of the principal Catacombs in order. As a rule the “Pilgrim Itineraries” class the different groups of cemeteries (Catacombs) under the different heading of the Roman road in the immediate vicinity of which they were excavated. Thus cemeteries are classed together which are situated on the “Via Aurelia,” the “Via Portuensis,” the “Via Appia,” the “Via Salaria Nova,” etc. This topographical arrangement was drawn up evidently for the convenience of these pilgrim travellers, who were thus guided in turn round the principal shrines. ON THE RIGHT BANK OF THE TIBER IN THE TRASTEVERE QUARTER THE VIA VATICANA. (_The Vatican Cemetery._) The allusion referred to here is to the crypts existing beneath the great basilica of S. Peter.--“No man knows what the number is of the holy martyrs who rest in this Church” (Etenim nullus hominum scit numerum sanctorum Martyrum qui in eadem ecclesia pausant).--_Itinerary of William of Malmesbury._ This “Guide” was probably published for the use of the Crusaders. It was evidently made from a much older document, for many of the shrines alluded to in it belonged to Catacombs which in William of Malmesbury’s time had been long forgotten. THE VIA AURELIA. (_The road leading to Civita Vecchia._) After speaking of the shrines of certain celebrated confessors buried in a cemetery hard by this road, we read how “these lie buried with many (other martyrs)” (cum multis sepulti jacent).--_De Locis SS. Martyrum._ Of this “Itinerary,” the full title of which is “De Locis SS. Martyrum quæ sunt foris civitatem Romæ,”--the MS. was found in the Salzburg Library. THE VIA PORTUENSIS. (_The road leading to Portus, the ancient port of Rome, constructed by Claudius._) Certain famous shrines are particularised, after which follow the words: “Then you go down into a cave (or crypt), and you will find there an innumerable multitude of martyrs” (invenies ibi innumerabilem multitudinem martyrum); and again, alluding to another spot, “that cave (or crypt) is filled with the bones of martyrs.” The cemeteries on the Via Portuensis include the cemeteries of Pontianus and S. Felix.--_Salzburg Itinerary._ CEMETERIES (CATACOMBS) ON LEFT BANK OF THE TIBER (ROME PROPER) THE VIA OSTIENSIS. (_The road leading to Ostia._) After alluding to the sepulchre of S. Paul and other shrines, such as S. Adauctus, mention is made of a martyr Nomeseus, with many others (cum plurimis aliis). THE VIA ARDEATINA. (_A road on the right or west of the Via Appia._) The “Guide” speaks of various shrines and proceeds to say: “Not far off lie S. Petronilla and Nereus and Achilles and many other martyrs.”--_Itinerary of William of Malmesbury._ THE VIA APPIA. (_The “Queen of Roads” leads through Albano on to Capua._)