At regular intervals along the vallum—which, except the front on the N.N.E., exactly followed the edge of the plateau—were erected towers, or rather watch-towers, of timber. In addition to the supply from the wells within the limits of the camp, the Romans collected the water of the springs on the northern plateau, by means of pipes made of trunks of trees bored lengthwise and joined end to end. This channel followed the roadway G, and conducted the water into six good cisterns, hollowed out in the rock and lined with cement. There was a cistern under the Prætorium, and two for each of the legions.
On the western side palisades connected the smaller camp with the ditch sunk near the angle of the Prætorium; while on the eastern side of the plateau its escarpment rendered this precaution unnecessary.
The engineer entrusted with the setting out had disposed the fosse in an oblique direction, as shown in [Fig. 14], so as to present a larger front to assailants who, having taken the smaller camp, should present themselves on the place d'armes, H. The projecting angle was well defended by the Prætorium, and the obliquity of the vallum enabled the defenders making a sortie by the Prætorian gate, and by that marked F, to take the enemy almost in rear, and to drive them over the eastern declivity of the plateau.
Fig. 15.
The rampart walk of the vallum was raised three feet above the level of the camp, and was furnished with a cresting of stakes with wattling to retain the earth on the parapet (see [Fig. 15]). The fosse was twelve feet wide and seven deep, and was continued all round the camp, even on the sides where the declivities were steep.
The Némède was demolished. The Druids had it re-erected on the plateau in front of the camp, to the south, at the entrance of the wood. The inhabitants of the Val d'Avon were enjoined, under penalty of seeing their town destroyed, to abstain from injuring these intrenchments while unoccupied; they were even charged to keep them in repair, and to supply provisions to the troops who should be quartered there to protect the country against the invasions of the barbarians; for as Gaul was then tranquilized internally, and brought under the Roman sway, there was nothing to fear, except the attacks of the Germans, who were continually threatening the north-eastern provinces.
The camp was in fact occupied several times by Roman troops, and new works were successively planned and executed there. The country was fertile, and the position excellent, viz., between the large towns Châlons-sur-Saône (Cabillonum), Langres (Andrematunnum), and Autun (Bibracte). The camp received the name of Aboniæ Castrum, the town being thenceforth called Abonia—a name which it retained until the fourth century.
It was from Abonia that Vindex set out with a party of troops, which he assembled in the plains of the Saône, to rouse Gaul in revolt against Nero, and to give the empire to Galba. After the death of the Gallic hero, Galba wished to testify his gratitude to the towns and countries that had declared in his favour: and Abonia then acquired the title and rights of civitas, and enjoyed a long peace.