Lungotevere Tor di Nona

it.wikipedia records that the Carceri di Tor di Nona stood along this stretch, in a tower that passed to the hospital of the Compagnia del Salvatore in 1395 under the will of Giovanni di Jacobello Orsini, and that the name probably comes from its being the ninth tower counting from Porta Flaminia; the tower was anciently part of the city's defensive wall. From the early fifteenth century those prisons and the prisons of Corte Savella were together called the presone dello papa, a name they kept until 1657. The same source records that from Augustus' time the ground about 160 metres upstream of the Pons Aelius held one of Rome's two marble ports and the statio rationis marmorum, the imperial quarry-monopoly office; that landing was found in 1891, recorded, and destroyed during the building of the embankment walls.