For a nation that would have such a devastating impact on the greatest Empires of its day, we know almost nothing about the origin of the Huns. Early references are to peoples who can now be identified as having not been Hunnic, such as Scythians, Cimmerians, Parthians, etc.
The earliest positive reference to ‘Huns’ comes from 363 AD, when the Roman and Persian Empires concluded a hasty treaty after their usual round of mutually destructive campaigning was interrupted by the appearance of the Kidarites Huns from the Caucasus region. These were to prove a serious threat to both empires for years to come, but were never directly linked with the Hunnic tribes that were to ravage Western Europe less than a century later. It would be true to say that until 376 AD the civilised world at large remained ignorant of the terrible threat that lurked beyond its borders.