The monumental tomb of Caecilia Metella stands at the third milestone of the Via Appia, the oldest of ancient Rome's consular highways.
One hundred Roman feet in diameter (29.5 m), the circular tomb was built during the 1st century BCE to honour Caecilia Metella, the daughter of Quintus Caecilius Metellus Creticus (consul in 69 BCE), and wife of Marcus Licinius Crassus, son of the famous general Marcus Crassus, who served under Julius Caesar.
The upper section of the rotunda is has a marble frieze of bucrania (ox heads) and garlands. Beneath the frieze is the inscription: CAECILIAE Q · CRETICI · F METELLAE · CRASSI (To Caecilia Metella, daughter of Quintus Creticus, [and wife] of Crassus).
In 1303, the powerful Caetani family transformed the tomb, which is extremely well preserved, with much of its marble facing intact, into a crenellated tower to serve as the keep of the large castle they had built. The Caetani used the castle to control the traffic on the Via Appia and to collect tolls. In time the castle passed to the Savelli family and then to the Orsini, who held it until 1435, after which it became the property of the Roman Senate.