Roman buffer states

The Ghassanids, also known as the Jafnids, were an Arab Christian tribal confederation that migrated from South Arabia to the Levant in the 3rd century AD. There, they became clients of the Roman Empire, serving as foederati responsible for defending the eastern frontier of the empire against Bedouin raids and rival powers.

Osroene or Osrhoene (; ) was an ancient kingdom and region in Upper Mesopotamia. The Kingdom of Osroene, also known as the "Kingdom of Edessa" ( / "Kingdom of Urhay"), according to the name of its capital city (now Şanlıurfa, Turkey), existed from the 2nd century BC up to the 3rd century AD, and was ruled by the Nabataean Arab Abgarid dynasty. They were generally allied with the Parthians.

300px|thumb|Anatolia in the early 1st century AD with Commagene as a Roman client state Commagene () was an ancient Greco-Iranian kingdom ruled by a Hellenized branch of the Orontids, a dynasty of Iranian origin, that had ruled over the Satrapy of Armenia. The kingdom was located in and around the ancient city of Samosata, which served as its capital. The Iron Age name of Samosata, Kummuh, probably gives its name to Commagene.

thumb|right|370px|Approximate settlement area of the Quadi people in the late Roman era (3rd-4th centuries)

Dynasty which ruled the Kingdom of Armenia (AD 12-428)

thumb|Sculpted image of a Sarmatian from the Casa degli Omenoni

The Regni (also the Regini or the Regnenses) were a Celtic tribe, or group of tribes, living in Britain prior to the Roman Conquest, and later a civitas or canton of Roman Britain. They lived in what is now Sussex, as well as small parts of Hampshire, Surrey and Kent, with their tribal heartland at Noviomagus Reginorum (modern Chichester).

right|280px|Peoples of northern Britain according to Ptolemy's 2nd-century Geography

2nd-century Arab kingdom