مرغی دیدم نشسته بر باره‌ٔ توس
در پیش نهاده کله‌ٔ کیکاوس
با کله همی‌گفت افسوس افسوس
کو بانگ جرسها و چه شد نالهٔ کوس
Dashti, quatrain 33, p.250
morghi didam neshaste bar baare-ye tus
dar pish nehaade kalle-ye keykaaus
baa kalle hamigoft ke afsus afsus
ku baang-e jarashaa o che shod naale-ye kus
I saw a bird perched on the walls of Tus
Holding before it Kei Kavus's skull;
And to this skull it cried, 'Alas! Alas!
Where now the sound of bells, the roll of drums?'
Elwell-Sutton, In Search of Omar Khayyam, quatrain 33, p.192
Compare this quatrain to weblog Quatrain 24, which appears as an "Update":
آن قصر که بر چرخ همی‌زد پهلو
بر درگه او شهان نهادندی رو
دیدیم که بر کنگره‌اش فاخته‌ای
بنشسته همی‌گفت که کو کو کوکو
Dashti, quatrain 31, p. 249
aan qasr ke bar charkh hamizad pahlu
bar dargah-e u shahaan nehaadandi ru
didim ke bar kongoreash faakhtei
benshaste hamigoft ke ku ku ku ku*
From that royal palace which once rose to the sky
monarchs in splendor faced the world.
But on its turrets I have seen a ring-dove seated,
cooing, cooing over and over: where, where?
Michael Hillmann, Iranian Culture, 51
That palace vied with heaven to heaven surpass
with kings on display in court and pomp.
Perched high on a turret, we saw a dove ,
coo-coo her refrain, gone where, gone where ?*
*ku, which is the sound of cooing, also means "where" in Persian!
The Palace to Heav'n his pillars threw,
And kings the forehead on his threshold drew—
I saw the solitary Ringdove there,
And "Coo, coo, coo," she cried; and "Coo, coo, coo."
FitzGerald, Stanza XX, 2nd edition only
"As Khayyām sees it, if the all-powerful Iranian emperors ... were unable to remain in the world for longer than their appointed time, then more ordinary mortals should be that much more certain of their own mortality and insignificance." Michael Hillmann, Iranian Culture, 56
Along these lines, as in Quatrain 24, a couplet of Hafez (ghazal 343.5, Khanlari, Qazvini, 351.6):
کی بود در زمانه وفا جام می بیار
تا من حکایت جم و کاووس کی کنم
key bud dar zamaane vafaa jaam-e mey biyaar
taa man hekaayat-e jam o kaavus-e key konam
When was life ever faithful?
Bring a cup of wine
and let me tell you the story of Jamshid and Key Kavus.
Translation & Discussion of the quatrain: I will let Elwell-Sutton's translation suffice since it is fairly literal. In the final line, Elwell-Sutton translates نالهٔ کوس,"the roll of drums", appropriate as a sound of a musical instrument and a sound of sadness and lamentation as it generallly connotes especially so in this context. Tus was a town in Khorasan, say, 40 kilometers north of Mashhad, destroyed in the late 14th century C.E. Tus was the birthplace and burial place of Ferdowsi. To suit the pre-historic context, it will have existed before historical times. Key Kaaus, Key Kavus (usually "Kay"), was the mythical king and son of Key-Qobad. To my knowledge he had no legendary connection to Tus. More detailed information about Key Kavus given in this article, Encyclopaedia Iranica online.