This colossal cylinder of travertine is the final resting place of, and unusual tribute to, a woman who linked two major families in late first century BC Rome. A large plaque beneath the frieze honours Cecilia as the daughter of Quintus Creticus (probably so-called for his triumph in Crete in 64BC) and the wife of Crassus (a relation of the Crassus who ruled in the triumvirate with Julius Caesar).
During the 14th century the powerful Caetani family, relatives of Pope Boniface VIII, incorporated the tomb into a fortress, adding the crenellations to the top; the frieze decorated with skulls gives this area its nickname Capo di bove (ox head). Inside is a roofless gallery with a row of headless, toga-clad Romans and other marble objects, including lapidary inscriptions, crematory urns and tomb decorations - all funerary statues that used to line the Appia Antica.
The spot where Cecilia was buried is a fine example of brick dome-making. Downstairs, pieces of the volcanic rock used in the construction of the ancient road can be seen. Outside and across the way are what's left of the church of San Nicola, a rare example of Gothic architecture in Rome, surrounded by further walls of the fortress, which once straddled the road. From this imposing spot the Caetani filled their coffers by exacting tolls from passing travellers.