Roman military forces. This list also contains the last mention of the "Thervingi" in a classical source. Although he did not refer to the Vesi, Tervingi or Greuthungi, Jordanes identified the Visigothic kings from Alaric I to Alaric II as the successors of the fourth-century Tervingian king Athanaric, and the Ostrogoth kings from Theoderic the Great to Theodahad as the heirs of the Greuthungi king Ermanaric. Based on this, many scholars have traditionally treated the terms "Vesi" and "Tervingi" as referring to one distinct tribe, while the terms "Ostrogothi" and "Greuthungi" were used to refer to another. Wolfram, who still recently defends the equation of Vesi with the Tervingi, argues 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. In addition, Wolfram interprets the Notitia Dignitatum as equating the Vesi with the Tervingi in a reference to the years 388–391. On the other hand, another recent interpretation of the Notitia is that the two names, Vesi and Tervingi, are found in different places in the list, "a clear indication that we are dealing with two different army units, which must also presumably mean that they are, after all, perceived as two different peoples". Peter Heather has written that Wolfram's position is "entirely arguable, but so is the opposite". Wolfram believes 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. 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. Many recent scholars, such as Peter Heather, have concluded that Visigothic group identity emerged only within the Roman Empire. Roger Collins also 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