A doctorate about Umman-Manda. The Umman-Manda or Troops of Manda was not a specific nation but rather a religious concept that formed on the basis of empiric evidence. That barbaric invasions are regular events and they are sanctioned by gods to destroy the civilisation. Then gods help to defeat the barbarians and civilisations restarts
The first such a barbaric tribe were the Gutians (~2200bc), while the last two tribes who got this title were the Medes and Cimmerians.
There is a chapter dedicated to a certain Arakhab who was a leader of Ma(n)da circa 1650bc. This name is quite close to Arakha the Armenian attested in Behistun. Henning proposed that this might be a Gutian name given the final -b. Some proposed a Medes link. But the author dismiss the Medes link and propose that he was a just a leader of a rebellious group with unknown ethnic affiliation.
The author discuss various etymologies of the term Manda and choose it's Sumerian origin.
Umman-manda (literally “Troops of Manda”) is an Akkadian compound expression used to denote military entities and/or foreign peoples in a diverse number of texts pertaining to separate periods of ancient Near Eastern history. The dissertation initially discusses the various difficulties in ascertaining the etymology of the second component of the term Umman-manda. A very plausible etymology is proposed based on new research on the semantic range of the Sumerian word mandum. The thesis then focuses mainly on the references made to the Umman-manda in the Neo-Assyrian and Neo-Babylonian sources, where it is used to denote the Cimmerians and Medes respectively. The starting point is that these references are making literary allusions to the Standard Babylonian version of the Cuthaean Legend. New information gained from these literary allusions provides insight into the significance of the term Umman-manda in the first millennium B.C.: it recalls the various attributes of the Umman-manda depicted in the Cuthaean Legend and applies these attributes to contemporary political events. The Cuthaean Legend envisions a powerful enemy that emerges unexpectedly from the distant mountains and establishes hegemony after a sudden burst of military power. This enemy will eventually be destroyed without the intervention of the Mesopotamian king. The thesis studies how the Neo-Assyrian and Neo-Babylonian sources allude to the Cuthaean Legend and in this way they identify the Cimmerians and the Medes as the Umman-manda.