The defending troops, "Exercitus Germaniae superioris" and "Exercitus Raeticus", consisted mostly of auxilia cohorts. From the 2nd century, the strategic reserve was formed from three legions stationed in "Mogontiacum/"Mainz, "Argentorate/"Strasbourg and "Castra Regina"/Regensburg. The monitoring of the Upper Rhine was the responsibility of the "Classis Germanica"; that of the Rhaetic Danube came under the "Classis Pannonia", whose headquarters was in "Aquincum"/Budapest. Legions and auxilia cohorts were under the command of the governor. From the 3rd century the Upper Germanic-Rhaetian border troops ("comitatenses, repenses", and "liburnaria"), were commanded by three generals: