The CŠlian hill,( Caelius Mons) ( Regio I) the name of which comes from an Etruscan Chief called CŠlius CŠlius Vibennus, is situated in the south of Rome between the Esquiline and the depression where the Via Appia is running. The great Aqua Claudia aqueduct goes through the whole hill down to the Palatine. Before the Imperial era the CŠlius was very seldom mentioned. We know that a violent fire under Tiberius completely burnt down the buildings. The reconstruction allowed to build splendid mansions (domus) that turned the CŠlius into a rather smart area.

Built in the north-west part of the CŠlius, in the centre right of the picture, the , Great Nero’s Market ( Macellum Magnum ). Farther left the Temple of CamœnŠ, a sabine temple. It was in this temple that the magistrates deposited the inventory tables of the citizen’s fortune.

The Great Nero’s Market in a closer view. In front of the fašade of the Great Market, the Querquetulanus, a park planted with oaks. Querquetulanus might have been the antique name of the CŠlius.

Here, in the centre of the picture, in the west angle of the CŠlius, the valley of CamœnŠ ( Camenae)and the sacred wood with, in the middle, the source that gushed out of a grotto. The CamœnŠ were prophetic nymphs belonging to the old italic religion. Some texts assimilate them to the Muses.

South of the sacred CamœnŠ wood, on the Vicus Cyclopis, appears the Barracks of the Vth cohort of the Security Guards ( Cohors V Vigilum ) in the centre of the picture. A great rectangular building, rather imposing. At the bottom of the picture, quite close to the barracks, the House of L. Marius Maximus Perpetuus who was a consul in 198. At the foot of the promontory of this Domus, was a crevice or a hole known as the Den of the Cyclops from which the name of Vicus Cyclopis comes.

The alien Roman soldiers, the peregrins , ( free men who are neither Roman nor Latins), had their own barracks on the other side of the Vicus Cyclopis. The Castra Peregrina belonged to a complex of buildings with a prison and a temple, the temple of Jupiter Redux that can be seen here on its side. Last a portico, the Aedicula Genii Castrorum , closed the courtyard towards the great aqueduct.