The first edifice has the shape of a square hall with three apses,--_cella trichora_. It is built over the part of the catacombs which was excavated at the time of Pope Fabianus (A. D. 236-250), who is known to have raised _multas fabricas per cæmeteria_; it is probably his work, as the style of masonry is exactly that of the first half of the third century. The original _schola_ was covered by a wooden roof, and had no façade or door. In the year 258, while Sixtus II., attended by his deacons Felicissimus and Agapetus, was presiding over a meeting at this place in spite of the prohibition of Valerian, a body of men invaded the _schola_, murdered the bishop and his acolytes, and razed the building nearly to the level of the ground. Half a century later, in the time of Constantine, it was restored to its original shape, with the addition of a vaulted roof and a façade. The line which separates the old foundations of Fabianus from the restorations of the age of peace is clearly visible. Later the _schola_ was changed into a church and dedicated to the memory of Syxtus, who had lost his wife there, and of Cæcilia, who was buried in the crypt below. It became a great place of pilgrimage, and the itineraries mention it as one of the leading stations on the Appian Way. When de Rossi first visited the place, fifty years ago, this famous _schola_ or church of Syxtus and Cæcilia was used as a wine-cellar, while the crypts of Cæcilia and Cornelius were used as vaults. Thanks to his initiative the monument has again become the property of the Church of Rome; and after a lapse of ten or twelve centuries divine service was resumed in it on the twentieth day of April of the present year. Its walls have been covered with inscriptions found in the adjoining cemetery. The theory suggested by modern writers with regard to the _scholæ_ is very much the same as that concerning the _tablinum_ of private houses. At first the small building was sufficient to meet the wants of a small congregation; with the increase of the members it became a _presbiterium_, or place reserved for the bishop or the clergy, while the audience stood outside, under the shelter of a tent, or a roof supported by upright beams. Here also we have all the architectural elements of the Christian basilica. The name _schola_, in its original meaning, has never died out in Rome; and as in the Middle Ages we had the _scholæ_ of the Saxons, the Greeks, the Frisians, and the Lombards, so we have in the present day those of the Jews (_gli scoli degli ebrei_). [Illustration: PLAN OF SCHOLA ABOVE THE CATACOMBS OF CALLIXTUS (From Nortet's _Les Catacombes Romaines_)]