Vierkaiserjahr
During the Year of the Four Emperors (68–69), XV "Primigenia" and the other German border legions supported the claim of Vitellius to the throne, first against Galba and afterwards against Otho. When Vespasian was finally acclaimed undisputed emperor, the legions XV "Primigenia" and V "Alaudae" returned to Castra Vetera (Xanten camp), where the Batavian rebellion was already in progress.