Probably as a macellum (food market) a round structure was built in the second half of the second century AD. A pricelist from the 4th century on its sides, put there on orders of Emperor Diocletian to fight inflation. All prices of the commodities sold on markets throughout the empire were indicated. A strong male slave would go for 30.000 dinar, twice the amount for a donkey. Nowadays this list is seen as an indication the market held the first “exchange commodity” or “borsa” (comp. Fr. Bourse). I tend to disagree. Still it’s a nice spot.