This Legion was raised under the Emperor Caligula in 39 AD, when he needed more forces for his campaign in Germania. It was titled after his favorite Goddess, Fortuna, of whom the Latin firstborn term 'Primigenia' is a title. That autumn, the Legion marched across the Alps to the Middle Rhine, where it first saw action at Wiesbaden. It was later based at Mainz in Germania Superior, then at Xanten in Germania Inferior. In 47, it was part of an expeditionary force led by General Corbulo against the Frisians and Chauci. When the Emperor Claudius ordered Rome's border to be kept at the Rhine, the Legion built fortifications along its banks, including a canal from Matilo (Leiden) to Voorburg that still exists today. In the chaotic period after Emperor Nero's position had become untenable, the Legion marched south and defeated Vindex, who was supporting Galba's bid for the throne. When the Senate recognized Galba as Emperor, however, the Legion's conduct was seen as obstruction of accession. Although one soldier of the Legion would soon be able to exact their revenge. The Army of Germania Inferior, including the 15th Primigenia, proclaimed their commander Vitellius Emperor, crossed the Alps, and marched on Rome. Rome panicked, named Otho Emperor, and lynched Galba. One soldier of the Legion, a Camurius, happened to be present in Rome and was able to give the final blow during the lynching. The Legion helped Vitellius defeat Otho, but Vitellius was soon defeated by Vespasian and his superior forces. When the Batavians revolted in Germania Inferior in late 69, the Legion was one of those eventually besieged at Xanten, and forced to surrender in 70 along with a number of other Legions. It was never reconstituted.