This storied Legion (and its twin, XV Primigenia) was founded in 39 AD by Emperor Caligula, who needed more forces for his Germanic Campaign. His numbering twin Legions seven numbers apart is probably because for the Campaign, the 15th Primigenia was to support the 14th Gemina in Germania Superior, and the 22nd Primigenia was to support the 21st Rapax in Germania Inferior. It was titled after Caligula's favorite Goddess, Fortuna, of whom the Latin firstborn term 'Primigenia' is a title. The Legion first saw action at Wiesbaden in 39, then against the Chauci and Chatti in Germania. It was afterwards based at Mainz in Germania Superior. During the Civil War of 69, the Legion sided with Vitellius, helping him become Emperor, albeit briefly, as Vespasian soon defeated him. While that conflict raged in Rome, the Batavians staged a massive revolt in Germania, defeating and besieging the 5th Alaudae and 15th Primigenia at Xanten. The 22nd Primigenia was one of the Legions sent by Vespasian to resuce them. Although the inability to defend both Germanic Provinces from being overrun forced the surrender of the two besieged Legions, the 22nd Primigenia successfully defended Mainz before its eventual capture as well. Several months later, after Vespasian had been able to recover those Provinces, the Legion rebuilt the fortress at Xanten. In 89, the Governor of Germania Superior (Saturninus) tried to overthrow Emperor Domitian. The army of Germania Inferior, including the 22nd Primigenia, quickly defeated the rebel, and for the first time was granted the temporary honorary title 'Pia Fidelis' (Loyal and Faithful). It afterwards returned to Mainz, where it stayed for over two centuries. Among its officers during those years would be the future Emperors Hadrian, Didius Julianus, and Laelianus. Soldiers of the Legion also took part in the construction of both Hadrian's Wall and the Antonine Wall. Units of the Legion fought against the Mauri under Antoninus Pius in 144-52, in Lucius Verus' Parthian War in 161-66, and in Marcus Aurelius' campaigns against the Marcomanni in 166-74. Like the other Legions along the Rhine, it took no part in the Civil War after the death of Pertinax in 193, but when Lucius Severus fought his western rival Clodius Albinus and attacked the Rhine, the Legion defended Trier and fought at the decisive Battle at Lyon. It fought in Caracalla's successful Germanic Campaign in 213, and under Severus Alexander against the Persian Sasanians in 232. After supporting Emperor Gallienus in the Civil War of 260-68, it was again awarded the title 'Pia Fidelis' for the seventh and last time in the Legion's history. It also fought in Gallienus' campaigns against the invading Visigoths in 268. The Legion still existed at the beginning of the fourth century, but it's no longer recorded after the reign of Constantine I (306-37). Its emblem was the capricorn, which was a symbol of the Goddess Fortuna.