Legio XXII Primigenia was a legion of the Imperial Roman army dedicated to the goddess Fortuna Primigenia. Founded in AD 39 by the emperor Caligula for use in his campaigns in Germania, the XXII Primigenia spent much of their time in Mogontiacum up to the end of the 3rd century. The legion's symbols were a Capricorn and the demigod Hercules.

Mainz is the capital and largest city of the German state of Rhineland-Palatinate, and with around 221,000 inhabitants, it is Germany's 35th-largest city. It lies in the Rhine-Main Metropolitan Region—Germany's second-largest metropolitan region after Rhine-Ruhr—which also encompasses the cities of Frankfurt am Main, Wiesbaden, Darmstadt, Offenbach am Main, and Hanau.