Cadusii Our Proto-Vikings?

Information from Wiki.

Azerbaijan is the largest country in the Caucasus region located at the crossroads of Western Asia and Eastern Europe, it is bounded by the Caspian Sea to the east, Russia to the north, Georgia to the northwest, Armenia to the west, and Iran to the south. The exclave of Nakhchivan is bounded by Armenia to the north and east, Iran to the south and west, while having a short borderline with Turkey to the northwest.

The earliest evidence of human settlement in the territory of Azerbaijan dates to the late Stone Age and is related to the Guruchay culture of the Azykh Cave. The Upper Paleolithic and late Bronze Age cultures are attested in the caves of Tağılar, Damcılı, Zar, Yataq-yeri and in the necropolises of Leylatepe and Saraytepe.

Early settlements included the Scythians in the ninth century BC. Following the Scythians, Iranian Medes came to dominate the area to the south of the Aras. The Medes forged a vast empire between 900–700 BC, which was integrated into the Achaemenids Empire around 550 BC. The area was conquered by the Achaemenids leading to the spread of Zoroastrianism. Later it became part of Alexander the Great's Empire and its successor, the Seleucid Empire. Caucasian Albanians, the original inhabitants of the area, established an independent kingdom around the fourth century BC. During this period, Zoroastrianism spread in the Caucasus and Atropatene. Ancient Azerbaijanis spoke the Old Azari language.

Caucasian Albania is a name for the historical region of the eastern Caucasus, that existed on the territory of present-day republic of Azerbaijan (where both of its capitals were located) and partially southern Dagestan.

According to one hypothesis, Caucasian Albania was incorporated in the Median empire. Persian penetration into this region at a very early date is connected with the need to defend the northern frontier of the Iranian Empite.

[And this particularly fits with the character of "proto-Vikings":]

Another rebellion (of the Medes against the Persians), in 409 BC, against Darius II was of short duration. But the Iranian tribes to the north, especially the Cadusii, were always troublesome; many abortive expeditions of the later kings against them are mentioned. [How very much like Vikings do these troublesome Cadusii seem - the north from south regions were eventually partitioned from one another, perhaps on account of them - reminds me of Hadrian's Wall.]

During Seleucid rule, while southern Media, with Ecbatana, passed to the rule of Antigonus, and afterwards (about 310 BC) to Seleucus I, Atropates maintained himself in his own satrapy and succeeded in founding an independent kingdom. Thus the partition of the country, that Persia had introduced, became lasting; the north was named Atropatene (in Pliny, Atrapatene; in Ptolemy, Tropatene), after the founder of the dynasty, a name still said to be preserved in the modern form 'Azerbaijan'. [and here we have our link from the troublesome and fierce northern "Median" Cadusii tribe with the characteristics of Vikings to Azerbaijan]