In the same category with the Pilgrim Itineraries which the great Roman scholar has found so helpful in his Catacomb researches must be placed the celebrated papyrus preserved in the Cathedral of Monza. This is a contemporary catalogue or list of the sacred oils sent by Pope Gregory the Great (A.D. 590-604) to Theodelinda, Queen of the Lombards. The Lombard Queen sent a special messenger, one Abbot John, to Pope Gregory the Great asking him for relics of the saints buried in the Catacombs. At that period no portions of the sacred bodies were allowed to be removed, even at the request of so powerful a petitioner as Theodelinda; but as a substitute the Pope sent a little of the oil which fed the lamps which were ever kept burning before the tombs or shrines of the saints in question. Each phial containing the oil was carefully ticketed or labelled, and a list of these tickets or labels was written on this Monza papyrus. Some sixty or seventy saints’ shrines are specially enumerated, besides about eight places mentioned before which oils were kept burning, before tombs which contained a crowd of unnamed saints and martyrs. This Monza catalogue of the sacred oils De Rossi carefully compared with the topographical notices in the Pilgrim Itineraries above referred to. It was of great service to the scholar explorer in discovering and identifying many of the principal sanctuaries of the Catacombs. Another and quite a different material for his investigations De Rossi found amidst the desolate Catacombs themselves: he noticed that certain unmistakable indications ever marked the near neighbourhood of some historic crypt. 1. The existence above ground of more or less ruined basilicas of various dimensions,--in some cases showing the remains of a considerable building, in others of a comparatively small edifice as of a chapel or an oratory. Such a ruined building evidently pointed to there being beneath the soil, at times deep down, an historic crypt of importance. Such a small basilica or oratory had no doubt been built after the Peace of the Church in the middle or latter years of the fourth or in the fifth century, when pilgrimage to the shrines of the saints and martyrs had become the fashion. It was intended to accommodate the ever-growing crowds who came often from distant countries to pray near and to venerate the saints and martyrs whose remains lay buried in the crypt immediately beneath. 2. The remains, more or less perfect, of a staircase or staircases leading down to the sacred crypt containing a tomb of some great confessor known and honoured in the tradition of the Church.