The palatini were elite regiments 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...

 mostly attached to the comitatus praesentales, or imperial escort armies. In the elaborate hierarchy of troop-grades, the palatini ranked below the scholares (members of the elite cavalry regiments called the scholae

Scholae

Scholae is a Latin word, literally meaning "schools" that was used in the late Roman Empire to signify a unit of Imperial Guards. The unit survived in the Byzantine Empire until the 12th century...

), but above the comitatenses

Comitatenses

Comitatenses is the Latin plural of comitatensis, originally the adjective derived from comitatus , itself rooting in Comes .However, historically it became the accepted name for...

(regiments of the regional comitatus) and the limitanei

Limitanei

The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" The limitanei, meaning "the soldiers in frontier districts" (from the Latin phrase limes, denoting the military districts of the frontier provinces established in the late third...

(border troops).

The term derives from palatium ("palace") a reference to the fact that the regiments originally served in the imperial escort armies only. Later they were also found in the regional comitatus (mobile field armies). There, however, they continued to enjoy higher status and pay than the rest of the comitatus regiments. At the time 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...

was written (ca. 395 for the Eastern Empire), 80% of the regiments in the eastern comitatus praesentales were graded palatini and 14% of those in the regional comitatus.

The palatini were created by Constantine I

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...

 after he disbanded the Praetorian Guard

Praetorian Guard

The Praetorian Guard was a force of bodyguards used by Roman Emperors. The title was already used during the Roman Republic for the guards of Roman generals, at least since the rise to prominence of the Scipio family around 275 BC...

 in AD 312, and originally comprised former praetorians. As with all comitatus regiments, palatini cavalry regiments were called vexillationes (from vexillum

Vexillum

The vexillum was a flag-like object used in the Classical Era of the Roman Empire. The word is itself a diminutive for the Latin word, velum, sail, which confirms the historical evidence that vexilla were literally "little sails" i.e. flag-like standards...

= "military standard") and infantry regiments were either legiones or auxilia. Vexillationes palatinae are believed to have contained 400-600 men, legiones palatinae 800-1,200 and 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....

either 800-1,000 or 400-600.