Question

i need to find out who or what is being alluded in this poem, but google isnt helping.
Lest you should think that verse shall die,
Which sounds the silver Thames along,
Taught on the wings of truth to fly
Above the reach of vulgar song;

Though daring Milton sits sublime,
In Spenser native Muses play;
Nor yet shall Waller yield to time,
Nor pensive Cowley's mortal lay.

Sages and chiefs long since had birth
Ere Caesar was, or Newton named;
These raised new empires o'er the earth,
And those, new heavens and systems framed.
Vain was the chief's, the sage's pride!
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