The design of erecting a stone theatre in this quarter had been entertained by Julius Cæsar (Suetonius, "Cæsar," xliv.), but the carrying out of his adopted father's plan was reserved for Augustus (_ibid._, "Aug." xxix.). He did not, however, appropriate the honour of so great a work to himself, but transferred it to his beloved son-in-law, Marcellus. Great part of the outer walls of this large and splendid building still exists. Against these leaned the arches, supporting the tier of seats destined for the spectators. The greater portion of the vast halls have also been preserved; but being now converted into offices belonging to the Palace of the Orsini, which has insinuated itself into these ruins, they are not accessible to strangers. The lower story is in the Doric, the second in the Ionic, and the third was probably in the Corinthian order. It held 20,000 people. THE DECEMVIRAL PRISONS. Built by Appius Claudius for common offenders, _near_ the Forum Olitorium, and which site was afterwards occupied by the Theatre of Marcellus (Pliny, vii. 37). We have identified this prison, remains of which can still be seen under the theatre, consisting of chambers constructed in _opus reticulatum_. There are two splendid open archways of the same material leading into two large chambers, in the vaults of which are holes for letting the prisoners down. This we believe to have been the Decemviral Prisons and the scene of _Caritas Romana_. "Here youth offered to old age the food, The milk of his own gift." Byron visited the chambers under S. Nicola in Carcere, when he was moved to compose his beautiful lines. He had before him the scene, though not the site; his words are more applicable to these dungeons, and we may say with him,-- "There is a dungeon, in whose dim, drear light What do I gaze on?--Nothing." _Passing the Theatre, a narrow lane on the left leads to the remains of_ THE PORTICO OF OCTAVIA. Dedicated to Octavia by her brother Augustus (Suetonius, "Aug." xxix.). The principal portion still existing belonged to the great portal leading to the open space surrounded by corridors which gave the people shelter during rain. In this stood two temples, the one dedicated to Jupiter, the other to Juno. Pillars belonging to the latter may be seen in a house in the Via Pescheria, and remains of the Portico of Octavia at No. 12 Via Teatro di Marcello. The inscription on the architrave states that the building was restored by Septimius Severus and Caracalla. On the removal of two of the columns on which the pediment rested, their place was supplied by an arch of brickwork, thus preventing the building from falling in. Four columns and two piers are still standing of the inner row; of the outside only two columns remain, in addition to the two piers. The capitals are ornamented with eagles bearing thunderbolts. A flight of steps led up to this vestibule.