Of the nine legions remaining with Cæsar, three were sent with T. Labienus to the north towards the ocean, into the part of the country of the Eburones which touched on that of the Menapii; three to the south with C. Trebonius, to ravage the districts neighbouring on the Aduatuci (towards the south-west, between the Meuse and the Demer); lastly, Cæsar, at the head of the three others, advanced towards the Scheldt, the waters of which, at this period, mingled with those of the Meuse.[455] (_See Plate 14._) It was his intention to gain the extremity of the Ardennes (between Brussels and Antwerp), whither it was said that Ambiorix had retired with a few horsemen. He announced, on his departure, that he should return to Aduatuca on the seventh day, the period for the distribution of provisions to the legion which was left at that place in charge of the baggage. Labienus and Trebonius were, if they found it possible, to return at the same period, in order to concert again on the measures to be taken after they had made themselves acquainted with the designs of the enemy. The Eburones had neither regular force, nor garrison, nor _oppidum_. They formed a scattered multitude, always in ambush, attacking the soldiers when isolated, and obliging the Romans to carry on a harassing war, without any decisive result; for the nature of the country, covered with thick forests, and intersected by marshes, protected the barbarians, who could only be reached by small detachments. In the midst of these difficulties, Cæsar preferred doing less injury to the enemy, and sparing the lives of his own soldiers, by having recourse to the Gauls. He accordingly sent messages to invite the neighbouring peoples to come and ravage the territory of the Eburones, and assist him in exterminating a race guilty of having slaughtered his soldiers. At his call, numerous hordes rushed from all sides, and the entire territory of the Eburones was soon given up to pillage.[456] [Sidenote: The Sicambri attack Aduatuca.]