Catholic Encyclopedia (1913)/Arcosolium
This word is derived from arcus "arch" and solium, a term sometimes used by Latin writers in the sense of "sarcophagus"; solium porphyretici marmoris (Suet., Ner., 50). The term arcosolium was applied by the primitive Christians to one form of the tombs that exist in the Roman catacombs. Thus, an inscription published by Marchi (Mon. delle arti prim., 85), which may still be seen in the courtyard of the Palazzo Borghese, states that "Aur. Celsus and Aur. Hilaritas have had made for themselves and their friends this arcosolium, with its little wall, in peace." The arcosolium tombs of the catacombs were formed by first excavating in the tufa walls a space similar to an ordinary loculus surmounted by an arch. After this space was cleared an oblong cavity was opened from above downwards into that part of the rock facing the arch; a marble slab placed horizontally over the opening thus made completed the tomb, which in this way became a species of sarcophagus hewn out of the living rock. The horizontal slab closing the tomb was about the height of an ordinary table from the ground. In some instances, as in the "papal crypt" and the crypt of St. Januarius, the front wall of the arcosolium tomb was constructed of masonry. A species of tomb similar in all respects but one to the arcosolium is the so-called sepulchrum a mensâ, or table-tomb; in this a rectangular niche takes the place of the arch. The baldacchino tombs of Sicily and Malta belong also to this class; they consist of a combination of several arcosolia. A more ancient form of the arcosolium than that described consisted of an arched niche, excavated to the level of the floor, in which sarcophagi of marble or terra-cotta containing the remains of the deceased were placed. Arcosolium tombs were much in vogue during the third century in Rome. Many of the later martyrs were interred in them, and there are reasons to suppose that in such instances the horizontal slabs closing the tombs a served as altars on certain occasions. The arcosolia of the Roman cemeteries were usually decorated with symbolic frescoes, the vault of the arch and the lunette being prepared with stucco for this purpose. One of the most interesting examples of an arcosolium adorned in this manner may be seen in the catacomb of Sts. Peter and Marcellinus; in the lunette the miracle of Cana is represented as a symbol of the Eucharist, while on the arch a baptismal scene and a symbol of baptism - always associated with Eucharistic symbols - are depicted on either side of a veiled orans. A second excellent example of a decorated arcosolium, in the Cæmeterium Majus, represents on the arch our Saviour between two praying figures, and in the lunette Mary as an orans (unique in the catacombs), with the child Jesus. (See CATACOMBS.)
KRAUS, Real-Encyklop., I, 89, 90; LECLERCQ in Dict. d'arch. chrét., I.
MAURICE M. HASSETT