At the back of the so-called auguratorium we find a long series of rooms running in a line across the hill from north-west to south-east, which have vaulted roofs and are similar to those found below in the domus Gelotiana, before described. Cav. Rosa has inferred with reason from this and from the graffiti in these rooms that they formed a part of the offices and guard-rooms attached to that large portion of the palace which lay on the site now occupied by the gardens and the vast masses of brickwork at the northern corner of the hill. The graffiti to be seen here are chiefly the scribblings of soldiers’ names, rude sketches of ships and animals, and combats of gladiators. [Sidenote: Tiberiana domus.] Several passages of the Roman historians lead us to conclude that the suite of rooms occupied by Tiberius were situated here. It was from the Tiberiana Domus, as Tacitus relates, that Vitellius surveyed the conflagration of the Temple of Jupiter on the Capitol, and the engagement between his adherents and the Flavian party under Sabinus. The Tiberian part of the palace was also that through which, as Tacitus also tells us, Otho descended into the Velabrum, after joining Galba at the sacrifice in the Temple of Apollo on the Palatine.[27] Afterwards, the Tiberiana Domus became the favourite residence of Antoninus Pius and Marcus Aurelius, and it was probably during their reigns that the library which we find mentioned by Gellius was established here.[28] We now pass through the garden grounds which lie over the remains of the Domus Tiberiana, and descend on the side which looks over the Forum, by a long staircase through the immense masses of brickwork and concrete which are said to have been part of the insane additions of Caligula to the imperial palace. He is declared to have made a passage from this wing of the palace to the back of the Temple of Castor below in the Forum, in order that he might appear in that sacred shrine as an equal of the twin gods and an object of worship when the Senate met there. He also joined this corner of the palace with the Capitoline Temple of Jupiter by a huge viaduct, which passed over the Basilica Julia, in order that he might thus make himself the contubernalis of Jupiter.[29] Some of the substructions of this viaduct are to be seen near the back of the church of S. Maria Liberatrice. We now leave the Palatine by the Clivus Victoriæ, along which we entered, and turn to the arch of Titus and the ruins which stand near it. THE VELIA. [Sidenote: The Velia.]