The Regii or Reges was an auxilia palatina

Auxilia palatina

Auxilia palatina were infantry units of the Late Roman army, first raised by Constantine I as part of the new field army he created in about 325....

(light infantry) unit of the Late Roman army

Late Roman army

The Late Roman army is the term used to denote the military forces of the Roman Empire from the accession of Emperor Diocletian in 284 until the Empire's definitive division into Eastern and Western halves in 395. A few decades afterwards, the Western army disintegrated as the Western empire...

, active between the 4th and the 5th century. There was also a legio comitatensis with the same name.

History

This unit was probably formed under Constantius II

Constantius II

Constantius II , was Roman Emperor from 337 to 361. The second son of Constantine I and Fausta, he ascended to the throne with his brothers Constantine II and Constans upon their father's death....

 or Magnentius

Magnentius

Flavius Magnus Magnentius was a usurper of the Roman Empire .-Early life and career:...

, even if another reconstruction suggests they originated during the Constantinian

Constantine I

Constantine the Great , also known as Constantine I or Saint Constantine, was Roman Emperor from 306 to 337. Well known for being the first Roman emperor to convert to Christianity, Constantine and co-Emperor Licinius issued the Edict of Milan in 313, which proclaimed religious tolerance of all...

 period and formed by the Alamanni

Alamanni

The Alamanni, Allemanni, or Alemanni were originally an alliance of Germanic tribes located around the upper Rhine river . One of the earliest references to them is the cognomen Alamannicus assumed by Roman Emperor Caracalla, who ruled the Roman Empire from 211 to 217 and claimed thereby to be...

c king Crocus.

The Regii belonged to the army of the Caesar

Caesar (title)

Caesar is a title of imperial character. It derives from the cognomen of Julius Caesar, the Roman dictator...

Julian. They fought in the Battle of Strasbourg

Battle of Strasbourg

The Battle of Strasbourg, also known as the Battle of Argentoratum, was fought in 357 between the Late Roman army under the Caesar Julian and the Alamanni tribal confederation led by the joint paramount king Chnodomar...

 (357): they were deployed on the second line and held, together with the Batavi

Batavi (military unit)

The Batavi was an auxilia palatina unit of the Late Roman army, active between the 4th and the 5th century. It was composed by 500 soldiers and was the heir of those ethnic groups that were initially used as auxiliary units of the Roman army and later integrated in the Roman Empire after the...

, the pressure of the Alamannic cavalry that had repulsed the Roman cavalry.

In the Notitia dignitatum

Notitia Dignitatum

The Notitia Dignitatum is a unique document of the Roman imperial chanceries. One of the very few surviving documents of Roman government, it details the administrative organisation of the eastern and western empires, listing several thousand offices from the imperial court down to the provincial...

(395-420 circa) the Regii are listed in the army of the magister militum praesentalis of the East.