Thanks to @HS.Raghavendra for pointing out.
This melancholic song called now as the "Ballad of the King Vahram (वृत्रघ्नः)", supposedly composed in Persia during their muslim conquest.
I had heard that the royal families of Persia were Bhargavas in their gotra. So it is interesting to see them being referred to as "family of the Kavi".
Original lyrics:
Kay bavâd kû pêg-ê âyed az Hindûgân? (हिन्दवः)
Kû : "mad hân i Shâh Varhrân (क्षत्रः वृत्रघ्नः) az dûd ag î Kayân!" (कवयः)
Kê shpîl ast hazâr, abar sar-ô-sar ast pîlbân,
Ke abrâstag drafs dâred ped êvên î Husrôgân (सुश्रवसः)
pêsh-lashkar barend ped spâh-sâlârân!
Mard-ê visê abâyed kirdan zîrag targumân, (ತರ್ಜುಮೆಯವನು)
Ke shaved bê gôbed ped Hindûgân (हिन्दवः)
Kû amâh cê dîd az dast î Tâzîgân, (dogs, ethnic slur for Arabs)
Amâh azêr, avêshân côn shâhân, (क्षत्राः)
Bê stad hend pâdixshâyîh î az Husrôgân, (सुश्रवसः)
Nê ped hunar ud mardîh, côn Erân, (आर्या इव )
Bê ped afsôs ud riyahrîh, côn Dêvân! (देवा इव)
Bê stad hend ped stahm az mardômân, (मर्त्याः, =पुरुषाः)
Abâz harâg âst Hend, sâg î grân, (सप्तसिन्धु)
Az amâh bê âyed hân Shâh Varhrâm, (क्षत्रः वृत्रघ्नः)
I Varzâvand (वर्चस्-?) az dûdag î Kayân , (कवयः)
Bê âvarem kên î Tâzîgân, (श्वानः)
Côn Rôstahm (स्रवस्तम्भः इव) âvurd sad kên î Syâvashân! (श्यावाश्वाः)
English translation:
When will a courier come from India?
(to say) that: “King Vahrām of the family of the Kavi has come,
Having a thousand elephants, being upon them an elephant-keeper,
Having raised banners, in the manner of the Husrô (Persian kings)
The advance-guards are led by the generals!
A man should be dispatched, a clever interpreter,
Who may go and tell to India,
What we have seen from the hands of the Arabs!
All at once they weakened the religion and killed the kings.
We (have become) inferior, they are like kings.
They have taken away the sovereignty from the Husrô,
Not by virtue and valour, like the noble Aryans,
But in mockery and scorn, like the demons.
By force they have taken away from men
They have demanded again the tribute, a heavy impost.
From us shall come that king Vahrâm,
Possessing marvellous power, of the family of the Kavi.
We will bring vengeance in the Arabs,
As Rostam brought a hundred to the Syavashan.