Nomenclature: Vesi, Ostrogothi, Tervingi, Greuthungi
Contemporaneous references to the Gothic tribes use the terms "Vesi" (Latin for Visigoths), "Ostrogothi", "Thervingi", and "Greuthungi". Most scholars have concluded that the terms "Vesi" and "Tervingi" were both used to refer to one particular tribe, while the terms "Ostrogothi" and "Greuthungi" were used to refer to another. Herwig Wolfram points out that while primary sources occasionally list all four names (as in, for example, Gruthungi, Austrogothi, Tervingi, Visi), whenever they mention two different tribes, they always refer either to "the Vesi and the Ostrogothi" or to "the Tervingi and the Greuthungi", and they never pair them up in any other combination. This conclusion is supported by Jordanes, who identified the Visigoth (Vesi) kings from Alaric I to Alaric II as the heirs of the 4th century Tervingian king Athanaric, and the Ostrogoth kings from Theoderic the Great to Theodahad as the heirs of the Greuthungi king Ermanaric. In addition, the Notitia Dignitatum equates the Vesi with the Tervingi in a reference to the years 388–391.
The earliest sources for each of the four names are roughly contemporaneous. The first recorded reference to "the Tervingi" is in a eulogy of the emperor Maximian (285–305), delivered in or shortly after 291 (perhaps at Trier on 20 April 292)[b] and traditionally ascribed to Claudius Mamertinus.[c] It says that the "Tervingi, another division of the Goths" (Tervingi pars alia Gothorum), joined with the Taifali to attack the Vandals and Gepidae. (The term "Vandals" may have been a mistaken reference to the "Victohali", since around 360 the historian Eutropius reports that Dacia was currently inhabited by Taifali, Victohali, and Tervingi.)[d] The first recorded reference to "the Greuthungi" is by Ammianus Marcellinus, writing no earlier than 392 and perhaps later than 395, recounting the words of a Tervingian chieftain who is attested as early as 376. The first known use of the term "Ostrogoths" is in a document dated September 392 from Milan. (Claudian mentions that they, together with the Gruthungi, inhabit Phrygia.)
Wolfram notes that "Vesi" and "Ostrogothi" were terms each tribe used to boastfully describe itself and argues that "Tervingi" and "Greuthungi" were geographical identifiers each tribe used to describe the other. This would explain why the latter terms dropped out of use shortly after 400, when the Goths were displaced by the Hunnic invasions. As an example of this geographical naming practice, Wolfram cites an account by Zosimus of a group of people living north of the Danube who called themselves "the Scythians" but were called "the Greutungi" by members of a different tribe living north of the Ister. Wolfram believes that the people Zosimus describes were those Tervingi who had remained behind after the Hunnic conquest. For the most part, all of the terms discriminating between different Gothic tribes gradually disappeared after they moved into the Roman Empire. The last indication that the Goths whose king reigned at Toulouse thought of themselves as "Vesi" is found in a panegyric on Avitus by Sidonius Apollinaris dated 1 January 456.
Most recent scholars (notably Peter Heather) have concluded that Visigothic group identity emerged only within the Roman Empire. Roger Collins believes that the Visigothic identity emerged from the Gothic War of 376–382 when a collection of Tervingi, Greuthungi, and other "barbarian" contingents banded together in multiethnic foederati (Wolfram's "federate armies") under Alaric I in the eastern Balkans, since they had become a multi ethnic group and could no longer claim to be exclusively Tervingian.
The term "Visigoth" was an invention of the 6th century. Cassiodorus, a Roman in the service of Theodoric the Great, invented the term "Visigothic" to match that of "Ostrogothic", terms he thought of as signifying "western Goths" and "eastern Goths" respectively. The western–eastern division was a simplification (and a literary device) of 6th century historians; political realities were more complex. Further, Cassiodorus used the term "Goths" to refer only to the Ostrogoths, whom he served, and reserved the geographical term "Visigoths" for the Gallo-Spanish Goths. This usage, however, was adopted by the Visigoths themselves in their communications with the Byzantine Empire and was still in use in the 7th century.
Other names for other Gothic divisions abounded. A "Germanic" Byzantine or Italian author referred to one of the two peoples as the Valagothi, meaning "Roman Goths", and in 469 the Visigoths were called the "Alaric Goths".
Etymology of Tervingi and Vesi/Visigothi
The name Tervingi may mean "forest people". This is supported by evidence that geographic descriptors were commonly used to distinguish people living north of the Black Sea both before and after Gothic settlement there, by evidence of forest-related names among the Tervingi, and by the lack of evidence for an earlier date for the name pair Tervingi–Greuthungi than the late 3rd century. That the name Tervingi has pre-Pontic, possibly Scandinavian, origins still has support today.
The Visigoths are called Wesi or Wisi by Trebellius Pollio, Claudian, and Sidonius Apollinaris. The word is Gothic for "good", implying the "good or worthy people", related to Gothic iusiza "better" and a reflex of Indo-European *wesu "good", akin to Welsh gwiw "excellent", Greek eus "good", Sanskrit vásu-ş "id.". Jordanes relates the tribe's name to a river, though this is most likely a folk etymology or legend like his similar story about the Greuthung name.