Structure The foundation of the Tomb of Caecilia Metella rests partially on
tuff rock and partially on
lava rock. The lava rock is part of an ancient lava flow from the
Alban Hills that covered the area 260,000 years ago. The core of the podium was cast in several layers of
concrete, ranging from .7 to .85 m thick. The thickness of each layer corresponds with the height of the
travertine facing-blocks that surrounded the podium, as the travertine was used as a frame in order to help the concrete layers form. The rotunda was built in this same fashion, travertine blocks on the outermost section with cement poured in the middle to give the concrete some structure and then covered in travertine
revetment, most of which has been stripped away. While the walls of the tower are 24 ft thick, comparatively the adjoining castle of the Caetani was made of a thin wall of
tufa. Originally the top of the monument would have been a cone-shaped
earthen mound, as conical shapes were common with Roman rotundas, but the earthen mound has long been replaced by medieval battlements. The Roman concrete was made up of semi-liquid mortar and aggregate, which consisted of broken pieces of stone or bricks. The aggregate is cobble-sized stone (the size of a fist). Mortar and concrete were alternated in the construction as the semi-liquid mortar would bind the stone pieces together. The mortar utilized the lava rock quarried from beneath the monument as an additive or substitute for sand in the concrete.
Interior The interior of the Tomb of Caecilia Metella can be separated into 4 sections: the
cella, the upper and lower corridors, and the west compartment. The most important being the cella which was used for funerary purposes and for "housing" the dead. The cella is a tall, circular shaft rising all the way through the center of both the podium and the rotunda. The cella is about 6.6 m in diameter at the bottom but tapers as it rises to a 5.6 m diameter at the top. The top features an oculus allowing for light. Throughout the cella, there are over 143 cut outs, divided into 12 rows of 10–14, in the walls of the cella that were used as
putlog holes in the creation of the monument. The upper corridors is believed to be the main entrance to the cella.
Exterior The upper section of the rotunda is decorated quite minimally with a marble frieze of bucrania, oxen heads, and garlands. Beneath the frieze is the famous inscription "CAECILIAE Decorations were very popular on funerary altars and votive offerings and the most famous example are identified in the frieze of carved ox skulls and festoons on the inside of the fence. Three types of bull heads can be distinguished: complete bovine head, skull of bull but still covered with skin, and a full skeletal skull. The inclusion of the naked skull is indicative of the termination of use of the complete bull skull and the skull with skin occurred around 30 BC and the inclusion of the use of particular bull heads allows for an approximate date to be made, as bull heads seen on dated monuments can be compared. The bull heads and garlands indicate and verify the timing of the creation of the monument. During the time period, the Roman decoration of bull heads was shifting and thus the representation of particular bull heads approximate the date.
Sarcophagus Today, there is a marble
sarcophagus located in
Palazzo Farnese that is purportedly from the Tomb of Caecilia Metella. According to literary sources, it was found in the cella and had been there since before the construction of the Caetani Castle. However, there is no definitive evidence to verify the sarcophagus as the sarcophagus of Caecilia Metella and many historians believe the sarcophagus does not belong to the monument and had been found in the surrounding area of the mausoleum rather than inside it. Recently, the sarcophagus was the object of a detailed study and the author of this study dates sarcophagus between AD 180 and 190. Further evidence suggesting this to not be the sarcophagus of Caecilia Metella is at the time of Caecilia Metella's death, cremation was the typical burial custom and a funerary urn is expected rather than a sarcophagus. In addition, records from 1697 of the Farnese Collection state the sarcophagus was registered without a specified provenience indicating even at the time, historians were unsure of the relationship between the sarcophagus and the tomb. ==Castrum==