PART I
INTRODUCTORY
The nature of the catacombs’ witness to the secret of the “Inner Life” of the Church--A brief sketch of the contents of the Fourth Book 219
I
THE ROMAN CATACOMBS--THEIR PLACE IN ECCLESIASTICAL HISTORY
Early researches--Their disastrous character--De Rossi--His view of the importance of the testimony of the catacombs in early Christian history--Much that has been considered legendary is really historic--Witness of catacombs to the faith of the earliest Christians 223
II
DE ROSSI’S WAY OF WORKING IN HIS INVESTIGATIONS
Among the materials with which De Rossi worked may be cited: Acta Martyrum of S. Jerome, Liber Pontificalis, the “Pilgrim Itineraries,” and the “Monza” Catalogue, which is specially described--Decoration of certain crypts--Basilica (ruins) above ground--Luminaria--Graffiti of pilgrims--Inscriptions of Pope Damasus _in situ_, and also preserved in ancient syllogæ 226
Certain of his more important discoveries in the cemeteries of SS. Domitilla, Priscilla, Callistus--The yet later discoveries of Marucchi and others 230
III
GENERAL ACCOUNT OF THE VASTNESS AND SITUATION OF THE CATACOMBS
(1) The Vatican cemetery and the groups of catacombs on the right bank of the Tiber 232
IV
(2) On the Via Ostiensis--Basilica of S. Paul--Cemeteries on the Via Ardeatina--Grandeur of cemetery of S. Domitilla--The small basilica of S. Petronilla 236
V
(3) Groups of cemeteries on the Via Appia--S. Sebastian (_ad Catacumbas_)--Group of S. Callistus--The Papal crypt--S. Soteris--Catacomb of Prætextatus on left hand of the Via Appia--Tomb of S. Januarius in this catacomb 242
VI
(4) Cemeteries on the Via Latina and Via Tiburtina--S. Hippolytus--S. Laurence--S. Agnes’ cemetery on the Via Nomentana 248
VII
(5) Cemeteries on the Via Salaria Nova--S. Felicitas; the great cemetery of S. Priscilla, and the ancient Roman churches connected with it--Legends--Remains of basilica of S. Sylvester over the cemetery of S. Priscilla--Memories of S. Peter in this cemetery--Its waters--Recent discoveries--Popes buried in the basilica of S. Sylvester 258
VIII
(6) Unimportant cemeteries on the Via Salaria Vetus--S. Pamphylus--S. Hermes--S. Valentinus, etc. 274
APPENDIX I.--S. PETRONILLA
Suggested derivation of Petronilla--De Rossi and other scholars still hold to the ancient Petrine tradition--Reasons for maintaining it--Early mediæval testimony here--Traces of the early cult of this Saint 277
APPENDIX II.--TOMB OF S. PETER
Probable situation of the tomb in present basilica of S. Peter--Account of what was found in the course of the excavations in the seventeenth century, by Ubaldi, Canon of S. Peter’s, who was an eye-witness of the discoveries made in A.D. 1626, when the works required for the great bronze Baldacchino of Bernini were being carried out 279