The occupying troops, "Exercitus Germaniae Inferioris", consisted mostly of auxilia cohorts. From the 2nd century, the strategic reserve comprised three legions stationed in "Bonna/"Bonn, "Novaesium/"Neuss, "Vetera/"Xanten and "Noviomagus/"Nijmegen. The control and surveillance of the waters of the North Sea, the Rhine estuary and the Lower Rhine was the responsibility of the "Classis Germanica" whose headquarters was in "Colonia Claudia Ara Agrippinensium"/Cologne. Legions, auxilia and fleet units were commanded by the respective provincial governor. From the 3rd century the "ripenses" (river guards), "comitatenses", and "liburnaria" were under the command of the "Dux Belgicae secundae".