Kalidasa's Raghuvamsha tells of the family of Rama and his descendants, including the conqueror Raghu. The warrior Raghu leads a military expedition to Transoxiana. He defeats and subjugates local peoples along the way (presumably on his march through Central Asia) until he reaches the Vankshu, as the ancient Indians called the Oxus River. There, Raghu's army battles the Hepthalites, or White Huns, whom the Indians called Hunas and Mlecchas (barbarians). The Hepthalites are defeated, and the Raghuvamsha boasts of "The exploits of Raghu, whose valor expressed itself amongst the husbands of the Huna women, became manifest in the scarlet color of their cheeks."
Interestingly enough, the 6th century Gothic (or Alanic) historian Jordanes wrote that the Western Huns, upon the death of Attila, "disfigured their faces horribly, with deep wounds, so that the gallant warrior should be mourned not with the lamentations and tears of women, but with the blood of men." A similar custom was observed among the Kutrigurs, Turks, Magyars, and Tajiks. Presumably, this form of facial mutilation was widespread amongst the steppe peoples of Central Asia.
After crossing the Oxus, Raghu and his army encountered the Kambojas, an ancient Iranian people often mentioned in Indian texts. The Kambojas submitted to Raghu and offered him gifts and treasures. Evidently, the Kambojas dwelt in the vicinity of the Pamirs. Kalidasa describes the preponderance of walnut trees in the Oxus country and indeed, this particular region is still known for the cultivation of walnuts.
Curiously, the explicit reference to the Hepthalites seems to lend credence that Kalidasa lived and prospered in the 4th and 5th centuries AD during the rule of Chandragupta Vikramaditya and Kumaragupta, rather than in the 1st century BC. The Hepthalites were implacable enemies of the Imperial Guptas during this era, and were strong enough to launch dangerous invasions and even killed the Sassanian king Peroz I in the 5th century. The ancient Indians were patronizingly contemptuous of the mlecchas who lived beyond the Hindu Kush and scarcely mention any foreign peoples apart from those civilizations they traded with. The barbaric Hepthalites would have to have merited considerable importance to appear in Kalidasa's work, which makes it all the more likely that he lived during the era they were most active, placing him in the 4th-5th centuries.
It is not inconceivable that the literary figure Raghu was based on the historical figure of Chandragupta Vikramaditya, who himself gained fame as a conqueror for the Gupta empire and who subjugated foreign peoples such as the Sakas. Unless the tale is sheer propaganda, the White Huns must have indeed represented a threat in order for Raghu, or his Imperial Gupta prototype to have marched deep into Central Asia in order to fight the mlecchas in their own homeland. For all its aesthetic and literary value, Kalidasa's Raghuvamsha would also have served as a convenient glorification of the great poet's Gupta patrons.
Maenchen-Helfen, Otto (1973). The World of the Huns. Berkely: University of California Press.
Basham, A.L. (2000). The Wonder that was India (3rd ed.). London: South Asia Books. ISBN 0-283-99257-3