When the catacombs began to be better known to the general public, and were visited by crowds of the devout or curious, they became one of the marvels of Rome. Travellers who so admired the _syringes_ or crypts of the kings of Thebes, calling them τἀ θαὑματα (the wonders), could not help being struck with awe at the great work accomplished by our Christian community in less than three centuries. An inscription found by Deville at Thebes, in one of the royal crypts, and published in the "Archives des missions scientifiques," 1866, vol. ii. p. 484, thus refers to the parallel wonders of Roman and Egyptian catacombs: "Antonius Theodorus, intendant of Egypt and Phœnicia, who has spent many years in the Queen-city of Rome, has seen the wonders (τἀ θαὑματα) both there and here." The allusion to the catacombs in comparison with the _syringes_ is evident. The inscription dates from the second half of the fourth century. To the edict of Milan, and to the peace which it gave to the Church, we must attribute the origin of the decadence of underground cemeteries. Burial in open-air cemeteries having become secure once more, there was no reason why the faithful should give preference to the unhealthy and overcrowded crypts below. The example of desertion was set by the Popes themselves. Melchiades (311-314), who was the first to occupy the Lateran palace after the victory of the Church, was the last Pope buried near his predecessors _in cœmeteris Callisti in cripta_. Sylvester, his successor, was buried in a chapel built expressly, above the crypt of Priscilla, Mark above the crypts of Balbina, Julius above those of Calepodius, and so on. Still, the desire of securing a grave in proximity to the shrine of a martyr was so intense that the use of the catacombs lasted for a century longer, although in diminishing proportions. When a gallery is discovered which contains more graves than usual, and has been excavated even in the narrow ledges of rock which separated the original loculi, or else at the corners of the crossings, which were usually left untouched, as protection against the caving-in of the earth, we may be sure we are approaching a martyr's altar-tomb. Sometimes the paintings which decorate a martyr's _cubiculum_ have been disfigured and their inscriptions effaced by an overzealous devotee. The accompanying cut shows the damage inflicted on a picture of the Good Shepherd in the cubiculum of S. Januarius, in the Catacombs of Prætextatus, by an unscrupulous disciple who wished to be buried as near as possible to his patron-saint. [Illustration: Cubiculum of Januarius.]