Legio XXII Primigenia
Legio XXII Primigenia (Latin for "Twenty-second legion Primigenia", dedicated to the goddess Fortuna Primigenia) was a Roman legion levied by Roman Emperor Caligula in 39, for his campaigns in Germania. There are still records of the XXII Primigenia in Mogontiacum (modern Mainz) from the end of 3rd century. The legion's symbols were a Capricorn and the demigod Hercules.
XXII Primigenia was first stationed in Mogontiacum in the Roman province of Germania Superior, guarding the Rhine border as part of the limes. Along with the rest of the Germanic army, the legion supported Vitellius in the Year of the four emperors (69). During the Batavian rebellion, XXII Primigenia, commanded by Gaius Dillius Vocula, was the only Germanic legion that survived attacks of the rebels and stayed in its camp, defending Moguntiacum. They remained in Moguntiacum until at least the 3rd century. Later Emperor Hadrian was tribunus militum of the XXIIth in 97-98.
The Rhine settlement was their main camp, but vexillationes of the legion participated in the building of the Antonine wall in Scotland (2nd century) and in the campaigns against the Sassanid Empire (around 235).
They were still in Moguntiacum during the attack of the tribe of the Alamanni in 235, and were responsible for the lynching of emperor Alexander Severus, when he tried to negotiate with the enemy, and the subsequent election of Maximinus Thrax as new emperor.
In 268, Primigenia probably fought under Gallienus at the Battle of Naissus, winning a victory over the Goths. The following year, Laelianus, the commander of the 22nd, became emperor of the Gallic Empire.
See also 
- List of Roman legions and Roman legion
- livius.org account
- official website of legio 22 reenactement group
- L.J.F. Keppie, Legions and Veterans: Roman Army Papers 1971-2000, p. 128