491 - 518, Huns were Byzantine allies (Procopius of Caesarea, 1a. pp. 112-113).
505 Huns turn over control over Derbent Pass to Persians, in exchange for annual payment (rent) (Procopius of Caesarea, 1a. p. 116)
527 Procopius Caesariensis: Hephthalites are people from Unn tribe, but they do not mix with them… they are not nomads like other Unn tribes, but live since ancient times in a fruitful country
531 Procopius Caesariensis: "Huns and Ants, Sklavens already crossed Danube many times and caused unrecoverable damage to Romans". Attack of Altynoba's Tatra Huns and Slavs on Byzantium.

Procopius: "Beyond the Sagins dwell many Hunnish tribes. The land is called Evlisia and barbarians populate the sea-coast and the inland up to the so called lake of Meotida and the river Tanais (Don). The people living there were called Cimmerians, and now they are called Utigurs. North of them are the populous tribes of the Antes." [21]

Procopius: "In the old days many Huns, called then Cimmerians, inhabited the lands I mentioned already. They all had a single king. Once one of their kings had two sons: one called Utigur and another called Kutrigur. 

Procopius further states that in his time kutrigurs lived west of the river Don "If you go from Bospor city to Kherson city, which is located in the coastal area and has long been subject to the Romans, all these lands between the two cities are inhabited by barbarians of the hunnish tribes .Book IV 5